七下数学书P76页4、5、6苏教版-分解因式

Question

限在一小时之内搞定，好的可以加分。帮忙吧！急急急急急急急

Answer 1

4(1)（a+b）^2+6(a+b)+9=(a+b+3)^2
(2)16-24(x-y)+9(x-y)^2=[4-3(x-y)]^2=(4-3x+3y)^2
(3)a^2-2a(b+c)+(b+c)^2=(a-b-c)^2
(4)4x^2-4x(y-1)+(y-i)^2=(2x-y+1)^2
5(1)-a+2a^2-a^3=-a(1-2a+a^2)=-a(a-1)^2
(2)3ax^2-3ay^2=3a(x^2-y^2)=3a(x+y)(x-y)
(3)16a^2b-16a^3-4ab^2=-4a(-4ab+4a^2+b^2)=-4a(2a-b)^2
6(1)a^4-1=(a^2+1)(a^-1)=(a^2+1)(a+1)(a-1)
(2)x^4-18x^2+81=(x^2-9)^2=(x+3)^2(x-3)^2
(3)x^4y^4-8x^2y^2+16=(x^2y^2-4)^2=(xy+2)^2(xy-2)^2
^2表示

Answer 2

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