分解因式x平方+7xy-搜答案-智慧作业帮

原式=(x-y)²-2(x-y)+1=(x-y-1)²

X平方+2XY+Y平方-2X-2y-3=(x+y)^2-2(x+y)-3=(x+y-3)(x+y+1)

（x-y）（x-y-2）-3

3x(x^2-2)y^2+6xy^2+9x^2y^2再问：O(∩_∩)O谢谢再答：原式=3x^3-6x^2y+3xy^2提取公因式，得3x(x^2-2xy+y^2)由完全平方公式，得3x(x-y)^2

x³y³—2x²y²+xy=xy(x²y²-2xy+1)=xy[(xy)²-2xy+1]=xy(xy-1)²

8(x^2-2y^2)-x(7x+y)+xy=8x^3-16y^2-7x^2-xy+xy=8x^3-16y^2-7x^2无法再分解

求根法：x^2+xy-2y^2+2x+7y-3=x^2+x(y+2)-2y^2+7y-3,△（x)=(y+2)^2-4(-2y^2+7y-3)=9y^2-24y+16=(3y-4)^2,x1=[-(y

7x²+3Y+XY+21X=7x²+21X+（3Y+XY）=7x（x+3）+Y（3+X）=（x+3）（7x+Y）

双十字相乘.

由x³-2x²y+xy²-x=x（x²-2xy+y²-1)=x[（x-y）²-1]=x（x-y-1）（x-y+1）.再问：分解因式：-49x

1x²+2xy-3y²=x²+2xy+y²-4y²=（x+y）²-(2y)²=(x+y+2y)(x+y-2y)=(x+3y)(x-

3x立方+12xy平方=3x(x²+4y²)

=7x²-4x²+4xy-y²=7x²-(2x-y)²=(√7x+2x-y)(√7x-2x+y)本题答案不唯一的

用反证法.假设此多项式能够分解成两个一次因式的积.设x^2-xy+y^2+x+y=(x+ay+b)(x+cy+d)x^2-xy+y^2+x+y=(x+ay+b)(x+y+d)=x^2+(b+d)x+(

x三次方-xy平方=x(x^2-y^2)=x(x+y)(x-y)

4x³-xy²=x(4x²-y²)=x[(2x)²-y²]=x(2x+y)(2x-y)

（x-y+z）(x-y-z)

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