分解因式：1／4-xy+y^2(x^2-1)^2+6(1-x^2)+9-2a^3b+4a^2b-2ab2x^2y^2-x

分解因式：
1／4-xy+y^2 =x/4-xy+y^2=(x/2-y)^2
(x^2-1)^2+6(1-x^2)+9 =(x^2-1)^2-6(x^2-1)+9=(x^2-1-3)^2=(x^2-4)^2
-2a^3b+4a^2b-2ab = -2a^3b+4a^2b-2a^b=-2 ab(a^2-2a+1)= -2 ab(a-1) ^2
2x^2y^2-x^4-y^4 = 2x^2*y^2-x^4-y^4=-( x^2- y^2) ^2=-((x+y)(x-y))^2
(a+b)^2+2c(a+b)+c^2= (a+b+c)^2
x^2-2xy+y^2-9= (x-y) ^2-9=( x-y+3)( x-y-3)
已知x-y=3,xy=10,求x^2+y^2及(x+y)^2的值.
x^2+y^2=(x-y) ^2+2 xy=9+20=29
(x+y)^2=(x-y) ^2+4 xy=9+40=49
已知a,b满足a(a+1)-(a^2+2b)=1,求a^2-4ab+4b^2-2a+4b的值
1=a(a+1)-(a^2+2b)= a^2+a- a^2-2b= a-2b  a=1+2b
a^2-4ab+4b^2-2a+4b=( a-2b) ^2-2 a+4b=1-2(1+2b) +4b=-1

(x^2-1)^2+6(1-x^2)+9=(x+2)^2(x-2)^2
已知x-y=3,xy=10,求x^2+y^2及(x+y)^2的值.29;49
已知a,b满足a(a+1)-(a^2+2b)=1,求a^2-4ab+4b^2-2a+4b的值 -1