第87页 - 课本苏科版七年级数学

$解:(1)原式=2a(x²-{y}^{4})$

$=2a(x+y²)(x-y²)$

$(2)原式=-(x²+2xy+y²)$

$=-(x+y)²$

$(3)原式=3a(x²+2xy+y²)$

$=3a(x+y)²$

$(4)原式=(a+b)(1-a²)$

$=(a+b)(1+a)(1-a)$

$解:(1)原式=(x²-9)(x²+9)$

$=(x-3)(x+3)(x²+9)$

$(2)原式=[(x²-2y)+(1-2y)][(x²-2y)-(1-2y)]$

$=(x²-1)(x²-4y+1)$

$=(x+1)(x-1)(x²-4y+1)$

$(3)原式={(x²)}^{2}-2{x}^{2}+1$

$=(x²-1)²$

$=(x+1)²(x-1)²$

$(4)原式=(x²-4y²)²$

$=(x+2y)²(x-2y)²$

$解：(1)原式=a(p-q+m). $

$ (2)原式=2x(2x-4y+1). $

$ (3)原式= 3xy(4z- 3x).$

$ (4)原式=3y³(y+3).$

$ (5)原式=3ab(2a-3b+5). $

$ (6)原式=-2a²(2a²+3a- 1).$

$解:(1)原式=b(2x-y)(4a+1). $

$(2)原式=2(b-1)²(3a-1).$

$解:(1)原式=(1+4a)(1-4a). $

$(2)原式= (m+3n)(m-3n).$

$(3)原式= (2x+9y)(2x-9y). $

$(4)原式=(3ax+ by)(3ax- by).$

$解:(1)原式=(x+5+2)(x+5-2)= (x+7)(x+3).$

$(2)原式=(a+b+a)(a+b-a)=b(2a+b). $
$(3)原式=(a²+b²+ab)(a²+b²-ab).$

$(4)原式=[7(a-6)+4(a+b)][7(a-6)-4(a+6)]=(11a- 3b)(3a- 11b).$

$解:(1)原式= (ab)²-2ab+1=(ab-1)²$

$(2)原式=3²-2×3×2a+(2a)²=(3-2a)²$

$(3)原式=(2x)²+2×2x×1+1²=(2x+1)²$

$(4)原式=x²-2×x×3y=(x-3y)².$

$解:(1)原式=[(a+b)+3]²=(a+b+3)²$

$(2)原式=[3(x-y)-4]²=(3x-3y-4)²$

$(3) 原式=[a-(b+c)]²=(a-b-c)²$
$(4)原式=[2x-(y-1)]²=(2x-y+1)²$

$解:(1)原式=-a(1-2a+a²)=-a(1-a)²$

$(2)原式=3a(x²-y²)=3a(x+y)(x-y)$

$(3)原式=-4a(-4ab+4a²+b²)=-4a(2a-b)²$

$(4)原式=(x+1)(x-1)(y+1)(y-1)$

$解:(1)原式=(a²-1)(a²+1)$

$=(a-1)(a+1)(a²+1)$

$(2)原式=(x²)²-2×x²×9+9²$

$=(x²-9)²$

$=(x-3)²(x+3)²$

$(3)原式=(x²y²)²-2×x²y²×4+4²$

$=(x²y²-4)²$

$=(xy-2)²(xy+2)²$

$(4)原式=x²({x}^{4}-{y}^{4})$

$=x²(x²+y²)(x²-y²)$

$=x²(x²+y²)(x+y)(x-y)$