分解因式..........我还是不会,在线等.........

来源:百度知道 编辑:互助问答吧 时间:2020/03/30 13:08:35
(1)16x^2-49y^2;
(2) 16a^2-72a+81;
(3) 4+12(x-y)+9(x-y)^2;
(4) x^3-9x;
(5)16x^4-1;
(6)6ab^2-9a^2b-b^3
做好有赏,不做别骂人.........
那个...........补充一下过程.........

16x^2-49y^2=(4x+7y)(4x-7y)
16a^2-72a+81=(4a-9)^2
4+12(x-y)+9(x-y)^2=(2+3x-3y)^2
x^3-9x=x(x+3)(x-3)
16x^4-1=(4x^2+1)(4x^2-1)=(4x^2+1)(2x+1)(2x-1)
6ab^2-9a^2b-b^3=-b(9a^2-6ab+b^2)=-b(3a-b)^2

(1)16x^2-49y^2;
=(4x+7y)(4x-7y)

(2) 16a^2-72a+81;
=(4a-9)^2

(3) 4+12(x-y)+9(x-y)^2;
=[2+3(x-y)]^2
=(3x-3y+2)^2

(4) x^3-9x;
=x(x^2-9)
=x(x+3)(x-3)

(5)16x^4-1;
=(4x^2+1)(4x^2-1)
=(4x^2+1)(2x+1)(2x-1)

(6)6ab^2-9a^2b-b^3
=-b(9a^2-6ab+b^2)
=-b(3a-b)^2

(1)16x^2-49y^2;
=(4x+7y)(4x-7y)
平方差公式
(2) 16a^2-72a+81;
=(4a-9)^2(完全平方公式)
(3) 4+12(x-y)+9(x-y)^2;
=[2+3(x-y)]^2
=(3x-3y+2)^2(完全平方公式)
(4) x^3-9x;
=x(x^2-9)(提x)
=x(x+3)(x-3)(平方差公式)
(5)16x^4-1;
=(4x^2+1)(4x^2-1)(平方差公式)
=(4x^2+1)(2x+1)(2x-1)(平方差公式)
(6)6ab^2-9a^2b-b^3
=-b(9a^2-6ab+b^2) (提-b)
=-b(3a-b)^2 (完全平方公式)
如果不会公式看http://baike.baidu.com/view/19859.htm

(1)(4x)^2-(7y)^2=(4x+7y)(4x-7y)

(2)(4a-9)^2

(3)[3(x-y)+2]^2

(4)x(x^2-9)=x(x+3)(x-3)

(5)(4x^2+1)(4x^2-1)=(4x^2+1)(2x+1)(2x-1)

(6)-b(b^2-6ab+9a^2)=-b(b-3a)^2

(4x+7y)(4x-7y)
(4a-9)^2
(3x-3y+2)^2
x(x+3)(x-3)
(2x+1)(2x-1)(4x^2+1)
-b(3a-b)^2

我不会骂你,但是我想对你说这种数学问题还是自己想明白了好,要不然以后考到了你还是不会