复杂方程计算专项练习题

1、小学复杂方程专项练习题(10) 1.6- (x- 0.45) =5,(10) 1.6- (x- 0.45) =5,(6) X+ (3X - 16) - =10 (X+1 ),4(10) 1.6- (x- 0.45) =5,(10) 1.6- (x- 0.45) =5,(1) 2x+5=5x - 7,(7)x+ 仁 x+3 ,2 2(10) 1.6- (x- 0.45) =5,(2) 3 (x- 2) =2 - 5 ( x- 2),(10) 1.6- (x- 0.45) =5,(10) 1.6- (x- 0.45) =5,6 (3x - 2)- 4 ( 4x- 3) =1 - 8x,(10) 1

2、.6- (x- 0.45) =5,(10) 1.6- (x- 0.45) =5,(3)- =146，(10) 1.6- (x- 0.45) =5,(10) 1.6- (x- 0.45) =5,4 (x - 2) +20x - 4=5 ( 1 - 2x),(10) 1.6- (x- 0.45) =5,(10) 1.6- (x- 0.45) =5,(4)5- (X+16.81 )=,5(10) 1.6- (x- 0.45) =5,(10) 1.6- (x- 0.45) =5,(5) 0.2x+，=8 -5(10) 1.6- (x- 0.45) =5,(16)2 (x+2 ) 3=3x 5,( 11

3、) 35 (x 2) 15 (5x 6) = ( 22x 63) 21 ( 3x 4),(12) x15+0.4=x T2 0.1 ,(17) x+ ( 3x 16)吃5%=10 (x+1 ),(13)150.5 4x=7-0.5x(18)丄 x 1.4=3.6+±x,43(19) 1.2:-43 5(14)x 2 丄=0.25 x,71123(15)5X+7.25-12 2.5X ,4(20)2x-=8+x(21) 8 (x - 2) =2x+7.(26) (X+12 ) X =42 - X ,5(25) x+ (3x - 16)吃5%=10 (x+2 ),(30)60-(x+10

4、 ) =5(25) x+ (3x - 16)吃5%=10 (x+2 ),(30)60-(x+10 ) =5(22) 6 (x- 3.5) =17.8+2x ,(27) 2 - (X - 0 55)=三:77(25) x+ (3x - 16)吃5%=10 (x+2 ),(30)60-(x+10 ) =5(25) x+ (3x - 16)吃5%=10 (x+2 ),(30)60-(x+10 ) =5(23) 5- (x+16.84) =0.2,7X (x+6 ) - 3x=4 X (2x+5),(25) x+ (3x - 16)吃5%=10 (x+2 ),(30)60-(x+10 ) =5(25)

5、 x+ (3x - 16)吃5%=10 (x+2 ),(30)60-(x+10 ) =5(29)=2.5,3x+5( 9+ X : ( 9 - X =5: 3,(25) x+ (3x - 16)吃5%=10 (x+2 ),(30)60-(x+10 ) =5(37) 3 (x+2 ) =4 (x+1),(31)： (28 - 2x) =6 (x - 5)s(36) 100 >0.5+ (x - 100) X).4=0.48x(41) 3 (2 - x) +5 (4x - 3) =4 ( x+1)(36) 100 >0.5+ (x - 100) X).4=0.48x(41) 3 (2

6、- x) +5 (4x - 3) =4 ( x+1)(32)64+( 2x - 5) =32(38) 二(x+2) =x+14(36) 100 >0.5+ (x - 100) X).4=0.48x(41) 3 (2 - x) +5 (4x - 3) =4 ( x+1)(36) 100 >0.5+ (x - 100) X).4=0.48x(41) 3 (2 - x) +5 (4x - 3) =4 ( x+1)(34) 1 - (x - 45%) =2.8,576 (x- 2) =52x - 32(36) 100 >0.5+ (x - 100) X).4=0.48x(41) 3

7、(2 - x) +5 (4x - 3) =4 ( x+1)(36) 100 >0.5+ (x - 100) X).4=0.48x(41) 3 (2 - x) +5 (4x - 3) =4 ( x+1)(35) 5 (X+4 ) =26.6 - X,81x - 342=76 (x - 2)(36) 100 >0.5+ (x - 100) X).4=0.48x(41) 3 (2 - x) +5 (4x - 3) =4 ( x+1)(36) 100 >0.5+ (x - 100) X).4=0.48x(41) 3 (2 - x) +5 (4x - 3) =4 ( x+1)(42)

8、15( 5.5 - x) =2x30%x+85=70%x+25 ,(46) 8 ( x- 2) =2 (x+7 ),(51) (10- x)吃=5x - 7(46) 8 ( x- 2) =2 (x+7 ),(51) (10- x)吃=5x - 7(43) 16+x=12+2x+x(44) 2 ( x- 4) =3 (x - 12)(49) 5x - 2 ( 3- 2x) =16x - 238.5X1.2 - 5.3x=8.5 - 4x(46) 8 ( x- 2) =2 (x+7 ),(51) (10- x)吃=5x - 7(46) 8 ( x- 2) =2 (x+7 ),(51) (10- x

9、)吃=5x - 7(45) 0.4- (4 - x) =1 呜(x - 5) >5 - 9= (x- 12) X12(46) 8 ( x- 2) =2 (x+7 ),(51) (10- x)吃=5x - 7(52) 2.7x - 1.8=1.2x+2.7 ,(53) 8 - 5 (6x+0.7) =10x+0.5 ,(57)= 13.51*5(58) X+ (3X - 16)吃5%=10 ( X+1 )(56) 3.5x+2=4x - 1,(61) 6 (x+1 ) =0.5 (10x+16),(56) 3.5x+2=4x - 1,(61) 6 (x+1 ) =0.5 (10x+16),

10、(59)75-(x+10 ) =2,(54) 8.5x- 3.9x=55.2 (x- 18),(56) 3.5x+2=4x - 1,(61) 6 (x+1 ) =0.5 (10x+16),(56) 3.5x+2=4x - 1,(61) 6 (x+1 ) =0.5 (10x+16),(55) 122 - x- 19= (x - 19) X5,(60) 5x - 3X (28 - x) =12+2x ,(56) 3.5x+2=4x - 1,(61) 6 (x+1 ) =0.5 (10x+16),(56) 3.5x+2=4x - 1,(61) 6 (x+1 ) =0.5 (10x+16),(62)

11、5 (x+2) =4 (x+9),(63) 127.5- (2x+3) =15,(68) 2.8x=19.32 - 6.4x,4x - 2 ( 5.5- x) =3.5x - 8,(66) 7 ( x+6)- 3x=4 (2x+5 ),(71) 2.6x=51.6 - 3.4x,(66) 7 ( x+6)- 3x=4 (2x+5 ),(71) 2.6x=51.6 - 3.4x,(64) 3 (x+2) =4 (x+1),(65) 8 ( x- 1.5) =x+0.6 ,(69) 5 (y - 4)- 7 ( 7- y)- 9=12 - 3 (9 - y),35 (x - 2) - 15 ( 5

12、x - 6) =22x - 63 - 21 ( 3x- 4),(66) 7 ( x+6)- 3x=4 (2x+5 ),(71) 2.6x=51.6 - 3.4x,(77) ( 0.6x+420 ) -(x+20) =3,(72) 3 ( 4x- 2 2 (3x+3 ) =9 - 8x,(76) 0.4 (x - 0.2) +1.5=0.7x - 0.38,(76) 0.4 (x - 0.2) +1.5=0.7x - 0.38,(73) 20+4x=6x - 24,(78) 35 (2- x) +15 (6- 5x) =22x+7+21 (4- 3x),(74) 5 ( x- 1) =x+1 ,

13、(79) 5 ( 3x - 4)- 2 (x - 1) =5 (2x - 1)(76) 0.4 (x - 0.2) +1.5=0.7x - 0.38,(76) 0.4 (x - 0.2) +1.5=0.7x - 0.38,(80)x=4.9+ x,353 ( 3x- 2) =10 - 0.5 (x - 3.5),(76) 0.4 (x - 0.2) +1.5=0.7x - 0.38,(76) 0.4 (x - 0.2) +1.5=0.7x - 0.38,(81) 3x+5 X =2x+ ' x',44 3(76) 0.4 (x - 0.2) +1.5=0.7x - 0.38,(

14、82) X £.2= (18 - x)弋,( 9+21 ) x=66x WO- 40 - 440,(86) (3x+4) +x=7 (x - 5)(91)-2,2(86) (3x+4) +x=7 (x - 5)(91)-2,2(83) 4 ( 4x- 6) =5 (3x+1 ),x- 2.5= (x- 1.8) >2(86) (3x+4) +x=7 (x - 5)(91)-2,2(86) (3x+4) +x=7 (x - 5)(91)-2,2(84) 10X=3 (2X+17) +45,(87) 12+ ( x- 12) > + x=x5 2(86) (3x+4) +x=

15、7 (x - 5)(91)-2,2(86) (3x+4) +x=7 (x - 5)(91)-2,2-X),(85) 5.7 (X - 0.2) =5.1 (X+0.6 ) +4 ,3 (X - 3) +4 ( 3X - 2) =7 (2(86) (3x+4) +x=7 (x - 5)(91)-2,2(86) (3x+4) +x=7 (x - 5)(91)-2,23X-22X+3 _3X+2:=(86) (3x+4) +x=7 (x - 5)(91)-2,24 330.2x+ + -x=8 x+ Wx,5 5554 o1.8x+=8,54 441.8x+ - =8 ,5 551.8x=7.2 ,

16、1.8x + .8=7.2 3.8 ,x=4(6) X+(3X16)3 =10 (X+1 ),4X+(3X16)X4=10X+10 ,X+12X 64=10X+10 ,13X -64=10X+10 ,13X 64+64=10X+10+64 ,13X=10X+74 ,13X 10X=10X+74 10X ,3X=74 ,3X £=74 3 ,T4X=331(7) x+1 = -x+3 ,2 23 d 11 Qx+1 x= x+3 1x ,2 2 22x+1=3 ,小学复杂方程专91题参考答案:(1) 2x+5=5x - 7 ,2x+5 - 2x=5x - 7 - 2x,3x - 7=5

17、 ,3x - 7+7=5+7 ,3x=12 ,3x -3=12 七,x=4;(2) 3 (x - 2) =2 - 5 (X- 2),3x - 6=12 - 5x,3x - 6+5x=12 - 5x+5x ,8x - 6=12 ,8x - 6+6=12+6 ,8x=18 ,8x 3=18 3,x=2.25 ;(3)(-)怎4=1 >24,466 (y+2)- 4 ( 2y - 3) =24 ,30 - 2y=24 ,30 2y+2y=24+2y ,2y+24=30 ,2y+24 24=30 24,2y=6 ,2y勺=6吃,y=3(4)5+( X+16.81 )=丄,515 + ( X+16

18、.81 ) X(X+16.81 ) X(X+16.81 ),5-X (X+16.81 ) =5 ,5x+1 1=3 1,x=2(8) 6 ( 3x 2) 4 (4x 3) =1 8x ,18x 12 16x+12=1 8x ,18x 16x+8x=0 ,10x=1 ,x=1 30 ,x= Id(5)0.2x+ =8 5-X (X+16.81 ) >=5 X5 ,5X+16.81=25 ,X+16.81 16.81=25 16.81 ,x=8.19(9) 4 ( x 2) +20x 4=5 (1 2x),4x 8+20x 4=5 10x ,24x+10x=5+12 ,34x=17 ,x=1

19、7 334 ,1x=:;1.6 3(x 0.45) =5 ,7.5X 守.5=5 彳5 ,X- 0.45=1.6 吒，x- 0.45=0.32 ,x=0.32+0.45 , x=0.77 ;(11 ) 35 (x - 2)- 15 (5x- 6) = (22x - 63)- 21 ( 3x- 4), 35x - 70- 75x+90=22x - 63 - 63x+84, 35x - 70 - 75x+90-22x+63x=22x - 63-63x+84-22x+63x x+20=21 ,X+20-20 =21 - 20 ,x=1(12 ) x 岀5+0.4=x 七-0.1 ,11 x+0.4=

20、x - 0.1 ,1512,1111x+0.4 - x=x - 0.1 -x,151512150.4+0.1x - 0.1+0.1 ,600.5 >60=-x >60,60x=30 ;X= .3(16)(17)(18)(13)150.5 - 4x=7-0.5x150.5 - 4x+0.5x=7-0.5x+0.5x150.5 - 3.5x=7 ,150.5 - 3.5x+3.5x=7+3.5x ,150.5 - 7=7+3.5x - 7,143.5%.5=3.5x £.5 ,x=41(14)4x 52=0.25 1 x ,711284x -c 51ecu12 +,=0.25

21、 一x+7112S2828ITx -2352=0.25112 (x+2) 3=3x 5 ,2x+4 3=3x 5 ,2x+1+5=3x 5+5,2x+6=3x ,2x+6 2x=3x 2x ,x=6 .x+ ( 3x 16) 勺5%=10 (x+1 ),x+12x - 64=10x+10 ,13x 64=10x+10 ,13x 64 10x=10x+10 10x ,3x - 64+64=10+64 ,x=_x 1.4=3.6+上 x ,431.4 x=3.6+ x331 x 121.4+1.4=3.6+1.4x=5 ,1217：x-2+2=0.25+2 ,11 11 1117 28 31 28

22、28x亍=2応亍,x=4(15 )5X+7.25=12 - 2.5X,45X+7.25+2.5X=12- 2.5X+2.5X ,47.5X+7.25=12,417.5X+7.25 - 7.25=12 一 - 7.25 ,47.5X=5 ,1x12l：=5x=60(19) 1.2 :(20)x=12 65,2 _o;x=,2亠2 6星;x；=一 x=9=8+xt-|-9(8+x 小,5x 2=24+3x ,5x 2 3x=24+3x 3x ,2x 2=24 ,2x 2+2=24+2 ,242x=26 ,2x煜=26勺,-X+ii=42 X ,5524x=13(21 )8 (x 2) =2x+7

23、,8x 16+16=2x+7+16 ,8x=2x+23 ,8x - 2x=2x+23 - 2x,6x=23 ,6x W=23 W,x=3 '6(22 )6 (x 3.5) =17.8+2x ,“=42 - X -=J. ,- X+X6x 21=17.8+2x ,6x 21 2x=17.8+2x 2x,4x 21+21 = 17.8+21 ,4x 韶=38.8 韶，x=9.7 ;x=(27) 2(X 0 55)7=: >7 (X 0 - 55) X (X 0.55)32X( X 0.55):(23 )5- (x+16.84 ) =0.2 ,5-( x+16.84 ) X (x+16

24、.84 ) =0.2 X(x+16.84 ),5=0.2x+3.368 ,5 3.368=0.2x+3.368 3.368 ,1.632 弋.2=0.2x -.2,x=8.16 ;(24 ) ( 9+ X： ( 9 X =5 : 3,3 (9+X ) =5 (9 X ),3 X9+3X=5 X9 5X ,27+3X=45 5X ,3X+5X=45 27,8X=18 ,8X -J=18 -J,X=2.25 ;(25 ) x+ ( 3x 16) -25%=10 (x+2),x+ (3x 16) - =10x+10 X ,4x+ ( 3x 16) X=10x+20 ,x+3x X4 16X4=10x

25、+20 ,x+12x 64=10x+20 ,x+12x 10x=20+64 ,3x=84 ,3x -3=84 3 ,x=282(26 ) (X+12 ) X =42 X ,522_X+12 X =42 X ,55_-：X(X - 0.55)广,77J X - 0.55) XA ,X 0.55=1,X 0.55+0.55=0.46875+0.55 ,X=1.01875 ;(28) 7 X(x+6) 3x=4 X(2x+5 ):7x+42 3x=8x+20 ,42+4x=8x+204x+20=42 ,4x+20 20=42 4x=22 ,4x -=22 , x=5.5 ;15(29)=2.5 ,3

26、k+515=2.5 X ( 3x+5 ),7.5x+12.5=15 ,7.5x+12.5 12.5=15 12.5 ,7.5x=2.5 ,7.5x 7.5=2.5 -.5,1x=；(30)60( x+10 ) =560(x+10 ) X (x+10 ) =520 ,(x+10)5x+50=605x+50 50=60 505x=10x=2(31 )- ( 28 - 2x) =6 (x - 5)811 亠x=6x 3024+30=6x+ x2427 81x=42八：x I427 2 27x=6(32 )64 - (2x 5) =32(38)二(x+2 ) =x+14x+ '=x+142&#

27、39;x+ l=x+1 -4-x=x. 1x=x2=0264-( 2x 5) X ( 2x 5) =32 X ( 2x 5)64x=160+64+'=0+:2 2 264x=2241 1x=4 264x W4=224 W4x=3.5(33 ) 81x 342=76 X (x 2)X=2 X2x=281x 342=76 X 15281x 76x=342 1525x=190(39)76(x - 2) =52x 3276x 152=52x 325x -5=190 苛x=382 (34 ) 1-5 (x 45% ) =2.8 ,51.45 (x 0.45) =2.8 ,x 0.45=1.4 5

28、.8,x 0.45=0.5 ,x 0.45+0.45=0.5+0.45 ,x=0.95(35 ) 5 (X+4 ) =26.6 X ,5x+20+x=26 ., 6 x+x ,6x+20 20=26.6 20,6x 55=6.6 55,(36 ) 100X0.5+ (x 100) X0.4=0.48x0.4x+10=0.48x0.4x+10 0.4x=0.48x 0.4x0.08x=100.08x 5).08=10 5).08x=125 .(37 ) 3 (x+2 ) =4 (x+1 ),3x+6=4x+4 ,3x+6 - 3x=4x+4 - 3x ,x+4=6 ,x+4 4=6 4 ,x=2

29、76x 152+152=52x 32+15276x=52x+12076x 52x=52x+120 52x24x=12024x 5?4=120 5?4x=5 .(40) 81x 342=76 (x 2)81x 342=76x 152 ,81x 342+342=76x 152+342 ,81x=76x+19081x 76x=76x+190 76x5x=1905x 55=190 5)x=38(41) 3 ( 2 x) +5 ( 4x 3) =4 (x+1)6 - 3x+20x - 15=4x+417x 9=4x+417x 4x+9 9=4x 4x+4+913x=1313x5 3=13 53x=1 ；

30、(42) 15 ( 5.5 x) =2x15 5.5+x=2x2x x=9.5x=9.5 ;7x=177x守=17弓(43) 16+x=12+2x+x16+x=12+3x3x x=16 122x=4x -2=4 吃x=2(44 ) 2 (x 4) =3 (x 12)2x 8=3x 362x 8 2x=3x 2x 368=x 368+36=x 36+36x=28 ;(45 ) 0.42 ( 4 x) =1 244= 1(4-x) =41.6=4 x1.6+x=4 x+x1.6+x=41.6+x 1.6=4 1.6x=2.4 ;(46 ) 8 (x 2) =2 (x+7 ),8x 16=2x+14

31、 ,8x 16 2x=2x+14 2x,6x 16+16=14+16 ,6x 2=30 2,x=5(47 ) 30%x+85=70%x+25 ,0.3x+85 0.3x=0.7x+25 0.3x ,0.4x+25=85 ,0.4x+25 25=85 25,0.4x=60 ,0.4x 2.4=60 2).4,x=150 ;(48 ) 8.5X1.2 5.3x=8.5 4x10.2 5.3x=8.5 4x10.2 5.3x+5.3x 8.5=8.5 4x+5.3x 8.51.3x=1.71.3x2.3=1.7 2.31717x=(50) (x 5) X5 9= (x 12) X25x 25 9=1

32、2x 1445x 34=12x 1445x 34 5x+144=12x 144 5x+1447x=1107x 2=110 2x=110(51) (10 x) 2=5x 710 x=10x 1410 x+x+14=10x 14+x+1411x=2411x 21=24 2124x=11(52) 2.7x 1.8=1.2x+2.7 ,2.7x 1.8+1.8=1.2x+2.7+1.8 ,2.7x 1.2x=1.2x+4.5 1.2x ,1.5x2.5=4.5 2.5,x=3 ;(53) 8 5 ( 6x+0.7 ) =10x+0.5 ,8 30x 3.5=10x+0.5 ,4.5 30x+30x=1

33、0x+0.5+30x ,4.5 0.5=40x 0.5 ,4-40=40x 20,x=0.1 ;(54) 8.5x 3.9x=55.2 (x 18),4.6x=55.2x 993.6 ,4.6x 4.6x=55.2x 993.6 4.6x ,50.6x 993.6=0 ,50.6x 993.6+993.6=993.6 ,50.6x=993.6 ,50.6x 20.6=993.6 250.6 , x=19.；(49 ) 5x 2 ( 3 2x) =16x 235x 6+4x=16x 23(55) 122 x 19= (x 19) X5 ,103 x=5x 95 ,103 x+x=5x 95+x

34、,103+95=6x 95+95 ,198 25=6x 2),x=33 ;X=74(56 ) 3.5x+2=4x - 1,3.5x+2 3.5x=4x 1 3.5x,2+1=0.5x 1+1 ,3 吒).5=0.5x 却.5,x=6(57)3+51*53.5 (X 16) =1.5X ,3.5X 56=1.5X3.5X 56+56=1.5X+563.5X 1.5X=562X=56X=28 ,(58 ) X+ ( 3X 16)七5%=10 (X+1 )X+ (3X 16) >4=10X+10X+3X >4 16>4=10X+1013X 64=10X+1013X 64+64=10

35、X+10+6413X=10X+7413X 10X=10X+74 10X3X=74(59 )75 - (x+10) =2 ,75-(x+10) X(x+10) =2 X(x+10),2x+20=75 ,2x+20 20=75 20,2x=55 ,2x勺=55煜，x=27.5 ;(60 ) 5x 3X( 28 x) =12+2x , 8x 84=12+2x ,8x 84+84=12+2x+84 ,8x=96+2x ,8x 2x=96+2x 2x,6x=96 ,6x -6=96 -6,x=16(61 ) 6 (x+1 ) =0.5 (10x+16 ),6x+6=5x+8 ,6x+6 6=5x+8 6

36、 ,6x 5x=5x+2 5x ,x=2(62) 5 (x+2 ) =4 (x+9 ),5x+10=4x+36 ,5x 4x=36 10 , x=26 ;(63) 127.5 -( 2x+3 ) =15 ,127.5 -( 2x+3 ) X ( 2x+3 ) =15 X ( 2x+3 ),15X( 2x+3) =127.5,15X( 2x+3 ) -5=127.5 -5 ,2x+3=8.5 ,2x+3 3=8.5 3 ,2x=5.5 ,2x £=5.5,x=2.75 ;(64) 3 (x+2 ) =4 (x+1 ),3x+6=4x+4 ,3x+6 3x=4x+4 3x ,x+4=6

37、,x+4 4=6 4 ,x=2 ;(65) 8 (x 1.5) =x+0.6 ,8x 12=x+0.6 ,8x 12+12=x+0.6+12 ,8x=x+12.6 ,8x x=x+12.6 x ,7x=12.6 ,7x -=12.6 -, x=1.8 ;(66) 7 (x+6 ) 3x=4 ( 2x+5 ),7x+42 3x=8x+20 ,4x+42=8x+20 ,4x+42 4x=8x+20 4x ,4x+20=42 ,4x+20 20=42 20 ,4x=22 ,4x -=22 4 , x=5.5 ;(67) 4x 2 ( 5.5 x) =3.5x 8 ,4x 11+2x=3.5x 8 ,

38、6x 11=3.5x 8 ,6x 11 + 11=3.5x 8+11,3.5x+3=6x ,3.5x+3 3.5x=6x 3.5x ,2.5x=3 ,x=47.:;2.5x £.5=3 £.5,x=1.2(68 ) 2.8x=19.32 6.4x ,2.8x+6.4x=19.32 6.4x+6.4x ,9.2x=19.32 ,9.2x £.2=19.32 £).2,x=2.1 ;(69) 5 (y 4) 7 ( 7 y) 9=12 3 (9 y),5y 20 49+7y 9=12 27+3y ,12y 78=3y 15,12y 78+78=3y 15+7

39、8 ,12y 3y=3y+63 3y,9y=63 ,9y £=63 £,y=7(70 ) 35 (x 2) 15 ( 5x 6) =22x 63 21 ( 3x 4),35x 70 75x+90=22x 63 63x+84 ,35x 75x 22x+63x= 63+84 90+70 ,x=1(71 ) 2.6x=51.6 3.4x ,2.6x+3.4x=51.6 3.4x+3.4x ,6x=51.6 ,6x £=51.6 £x=8.6;(72 ) 3 (4x 2) 2 ( 3x+3 ) =9 8x ,6x 12=9 8x,6x 12+8x=9 8x+8x

40、 ,14x 12=9 ,14x 12+12=9+12 ,14x=21 ,14x £4=21 £4,x=1.5 ;(73 ) 20+4x=6x 24 ,20+4x 4x=6x 24 4x ,2x 24=20 ,2x 24+24=20+24 ,2x=44 ,2x £!=44 £!,x=22 ;(74 ) 5 (x 1) =x+1 ,4x 5=1 ,4x 5+5=1+5 ,4x=6 ,4x £1=64 , x=1.5 ;(75) 3 ( 3x 2) =10 0.5 (x 3.5),9x 6=11.75 0.5x ,9x 6+0.5x=11.75 0.

41、5x+0.5x ,9.5x 6=11.75 ,9.5x 6+6=11.75+6 ,9.5x=17.75 ,9.5x£15=17.75 用.5,(75) 0.4 (x 0.2) +1.5=0.7x 0.38 ,0.4x+1.42=0.7x 0.38,0.4x+1.42 0.4x=0.7x 0.38 0.4x ,0.3x 0.38=1.42 ,0.3x 0.38+0.38=1.42+0.38 ,0.3x=1.8 ,0.3x £).3=1.8 £).3 , x=6;(76) ( 0.6x+420 ) £( x+20 ) =3 ,(0.6X+420) £

42、;(x+20 ) X(x+20 ) =3 X(x+20 ),3 (x+20) =0.6x+420 , 3x+60=0.6x+420 ,3x+60 0.6x=0.6x+420 0.6x ,2.4x+60=420 ,2.4x+60 60=420 60 ,2.4x=360 ,2.4x 吃.4=360 £.4 ,x=150 ;(77) 35 ( 2 x) +15 ( 6 5x) =22x+7+21(4 3x),160 110x=91 41x,160 110x+110x=91 41x+110x ,69x+91=160 ,69x+91 91=160 91 ,69x=69 ,69x £59=69 £i9 ,x=1(78) 5 ( 3x 4) 2 ( x 1) =5 ( 2x 1)15x 20 2x+2=10x 5 ,13x 18=10x 5 ,13x 18 10x=10x 5 10x