专题1整式的化简求值问题(重难点培优)-

222222222222222222222020-2021学年七年级数学下册尖子同步培题典北师大】专题整式化简求值问专题培优姓名：__________________注意事项：

班级：______________

得分：_________________本试卷满分100分，试题共24题选择10、填空、解答6道．答卷前，考生务必用0.5毫米黑色签字笔将自己的姓名、班级信息填写在试卷规定的位置．一选题本题10小，小3分，分）每题给的个选中只一是合题要的2020m22nA6BCD1+2m+n+2D2020a+2+b0aa+4b+22A0BCD6a+aba+2b2a+4abba+4abb4ab+4a+2aba0+0ab0A2020x+x+A2BCD61x+21

2222222222323232432222222222222323232432222212x1+x2xx12x+x+232020+4a0a2+43A13B113D

4a+4+812+1a+47a+44a+4a473D[2xx+1]x16A0B

C4D[22]2xx16[2xx+1]x+164xx2x+x2x+04xxB

2019xxy11+yA1

B132

D

222222mn+k+1010Cx++xy+1x+33+1+15D139ca++cabA48B76D4bc6a10ab+3a4cc10++cabB2019aa0mnmnhm+n4h3hkkh2n2020A2B

n

Dhmnhm20+nhmhnh3

k32aak32aa4aa24aaan1010k2019a2c

b﹣3c

A

B0

Db2ac

abbcc[b3]

ax52x÷xA5B

C25D5

÷4xx

4x

x

4

aa22222222222222222222222222aa2222222222222222222222222222xx5A二填题本题小题，小分共24分）把案接写横上112020xx13+2+221x+2+2xx5xxxxx102xx14222020x6x3

2+12x

26x6x2x60x26x+2+12xx62x3x6+83xx326262020xy

x+2++4+4yyx+4xyx+5yxyx2y

5

22232322222222222222222222223232222222222222222222542019[aabaab]b2019aa

a

+2b]ba20192019

+n2mn

+1+n2m+2+1+n2m2+1

+162020ab2+bb，a2

2020+712a+b

25

+b+ab6

222222222xy222222222xy2xy4222【解析】＝7，ab∴a+b＝＝7＝25．故答案为25．18春区期中）已知2a+3a﹣6＝0代数式3a）﹣1的值7【分析】原式提取公因式，并利多项式乘多项式法则化简，去括号合并得到最简结果，把已等式代入计算即可求出值．【解析】原式＝＝）＝2a＝2a，由﹣6，得到2a＝6，则原式6+1＝7故答案为7．三解题本题6小题共46分．答应出字明证过或算骤19秋县期末）求值（1）已知﹣4＝0，22的；（2）化简求值﹣1+，＝﹣2．【分析接利用同底数米乘法运算法则计算得出答案；（2）直接利用乘法公式化简，而合并同类项，再把已知数据代入得出答案．【解析∵x+y＝0，＝4，∴22＝2；（2）原式＝x＝（8x）÷4x﹣1，7

x222y22xy322222201920172x222y22xy322222201920172332420192018202020192017504948x2252020x+5y34322abm+x+530x+52+ax+52+54

x

32

2

282a+ab+ma+ab+ab+9，aa42020x++++1x+1

1x++1xx+xx+13++3+12+3+3++318

2233242019201820202020201920205049485122332223324201920182020202020192020504948512233244325n1nn3n20192018201732221x++1xx+xx+x113+3++3+1123[3+3+++1][312020x+1xx++1xx+x+111+x21+x++x323+3+3+14x+++10xx219

2233244355n1﹣2﹣3nnn1nn201920182233244355n1﹣2﹣3nnn1nn201920182017202020193243243232222222222222222234+11x++1x1x+x+1x+xxx121+x+1x1321x++x31+3+3

++3+133+3+14++1xx++xxxxx1xx+++10x1x1x+162020+

+b

a+b+b4+163ba2ab1y3xy

y12+n10p12mp+x+yxyxy4xy10

2222222222222222222222222222222222222222222222p13xy2x+y+2xy94x+＝+2xy412m+n1012nmpn﹣mp100+24