七年级数学上册导学案(40)(最新整理)

1、1. x+yz的相反数是（）.4.3 去括号axyzbxy+zcx+yzdx+y+z2. 将a2(2x3y)括号前面的符号变成相反的符号，正确的是（）aa+(4x+3y)ba+(4x+6y)ca+2(2x3y)da+2(3y2x)3. 下面各式去括号正确的是（）a a 2a6a2(3abc)=6a6a+b+cb(7x3y)2( 2b)=7x3y2 2bca(bc+d)=a+b+c+dd(a+1)+(bc)=a1bc4. 下列去括号中，错误的是（）a 5a2 - (a - 2b + 3c) = 5a2 - a + 2b - 3cb 2m + (-n + p) - (3t - m2 ) = 2m

2、- n + p - 3t + m2c 6x2 - 2(3x + 6) = 6x2 - 6x - 6d -(a + b) - (a2 + b2 ) = -a - b - a2 - b25. 根据去括号的法则，在中填上+或： (1)a(b+c)=ab+c；(2)a(bcd)=ab+c+d；(3)222222x +2x1=x (12x)；(4)x y 2y+2x=x +2x(y +2y)6.填括号：a+b+cd=a（）=a+（）7.去括号的法则是：括号前面是“+”时，把括号和它前面的“+”去掉，原来括号里的各项都 符号；括号前面是“-”时，把括号和它前面的“-”去掉，原来括号里的各项都符号8.填括号

3、：3x+2y24xy=（）=+（）9.(1)把多项式- 4 x2 + 3x - 5 写成单项式与二项式的差;5(2)把多项式 1 a2b - 2ab + 7ab3 + 6a2b2 写成两个二项式的和;310.下列去括号，正确的是（）aa-(3b-2c-1)=a-3b+2c-1b3x -2x -(-4x+1)=3x -2x -4x+1c2x -3(x-1)=2x -3x+1d-(2x-y)-(-a+2b)=-2x+y+a+2bn +1=211.3mn2 2mn()，括号里的代数式为()a22222n 1b2n mn+1c2n mn1dmn2n +1212.把x22xy+y2x+2y的二次项放在添

4、“+”号的括号里，把一次项放在添“”号的括号里，按 上述要求完成并正确的是()a2222x 2xy+y 2x+2y=(x +y )(2xy+2x2y)b2222x 2xy+y 2x+2y=(x 2xy+y )(2x2y)c2222x 2xy+y 2x+2y=(x +y )(2xy2x+2y)d2222x 2xy+y 2x+2y=(x 2xy+y )(2x+2y)答案：1b2.d3.d4.c5.(1)+；(2)；(3)；(4)6.bc+d，+b+cd 7.不改变，改变y +448.+3x2 2xy，3x+2y2xy9.答案不惟一，仅提供一种：(1) 3x - 4 x2 + 5 ; 5(2) 1

5、a2b - 2ab + (7ab3 + 6a2b2 ) 310.b11.c12.b“”“”at the end, xiao bian gives you a passage. minand once said, people who learn to learn are very happy people. in every wonderful life, learning is an eternal theme. as a professional clerical and teaching position, i understand the importance of continuou

6、s learning, life is diligent, nothing can be gained, only continuous learning can achieve better self. only by constantly learning and mastering the latest relevant knowledge, can employees from all walks of life keep up with the pace of enterprise development and innovate to meet the needs of the market. this document is also edited by my studio pr