第63页 - 苏科版七年级伴你学数学答案（上下册）

D

C

10000

-1

$解：原式=({x}^{2}+2xy+{y}^{2})-({x}^{2}-2xy+{y}^{2})$

$=4xy$

$解：原式=(9{m}^{2}-16{n}^{2})(9{m}^{2}+16{n}^{2})$

$=81{m}^{4}-256{n}^{4}$

$解：原式={[(-z+3x)(-z-3x)]}^{2}$

$={({z}^{2}-9{x}^{2})}^{2}$

$={z}^{4}-18{x}^{2}{z}^{2}+81{x}^{4}$

$解：原式=[a-(b-1)][a+(b-1)]$

$={a}^{2}-{(b-1)}^{2}$

$={a}^{2}-{b}^{2}+2b-1$

$解：原式=(4x+8)(4x-8)$

$=16{(x+2)}(x-2)$

$解：原式={x}^{4}+2{x}^{2}{y}^{2}+{y}^{4}-4{x}^{2}{y}^{2}$

$={x}^{4}-2{x}^{2}{y}^{2}+{y}^{4}$

$={({x}^{2}-{y}^{2})}^{2}$

$={(x+y)}^{2}{(x-y)}^{2}$

$解：原式=4xy-4{x}^{2}-{y}^{2}$

$=-(4{x}^{2}-4xy+{y}^{2})$

$=-{(2x-y)}^{2}$

$解：原式=({x}^{2}-{y}^{2}){(a-b)}^{2}$

$=(x+y)(x-y){(a-b)}^{2}$

$解：原式={({x}^{2}+4x+4)}^{2}$

$={(x+2)}^{4}$

$解：原式={(4{x}^{2}-9{y}^{2})}^{2}$

$={[(2x+3y)(2x-3y)]}^{2}$

$={(2x+3y)}^{2}{(2x-3y)}^{2}$