第62页 - 启东中学作业本七年级数学苏科版宿迁专版

C

A

m(m-3)

x(x+y)(x-y)

$ \begin{aligned}解：原式&=m²-2² \\ &=(m+2)(m-2). \\ \end{aligned}$

$ \begin{aligned}解：原式&=a²-(7b)² \\ &=(a+7b)(a-7b). \\ \end{aligned}$

$ \begin{aligned}解：原式&=2²-(xy)² \\ &=(2+xy)(2-xy). \\ \end{aligned}$

$ \begin{aligned}解：原式&=x(y²-36) \\ &=x(y-6)(y+6). \\ \end{aligned}$

解：原式=[(m+n)+n][(m+n)-n]

=m(m+2n).

解：原式=[(x+y)+(2x-y)][(x+y)-(2x-y)]

=3x(-x+2y).

B

2(a+2)(a-2)

xy(x+3)(x-3)

a(2x+3y)(2x-3y)

2022

4