四道分解因式：1.(x+y)²-4（x+y-1) 2.(x²+y²)²-4x²y²

-2x)².(x²-6x²+9(x-y)²+6y²+2(x².(x+y)²-2x)+1 43

解： 1.(x+y)²-4（x+y-1) =(x+y)²-4(x+y)+4 =(x+y-2)² 2.(x²+y²)²-4x²y² =(x²+y²+2xy)(x²+y²-2xy) =(x+y)²(x-y)² 3.(x²-2x)²+2(x²-2x)+1 =(x²-2x+1)² =(x-1)⁴ 4.(x+y)²-6x²+6y²+9(x-y)² =(x+y)²-6(x²-y²)+[3(x-y)]² =[(x+y)-3(x-y)]² =(x+y-3x+3y)² =(-2x+4y)² =4(x-2y)²

您好： x²-y²+4xy =（x²+4xy+4y²）-5y² = (x+2y)²-5y² =(x+2y+√5y)(x+2y-√5y) 如果本题有什么不明白可以追问，如果满意记得采纳 如果有其他问题请采纳本题后另发点击向我求助，答题不易，请谅解，谢谢。 祝学习进步！

+y²+6y²-y² 2; =;-4（x+y-1) =(x+y)²+2xy)(x²-2xy) =(x+y)² =(4y-2x)².(x+y)².(x+y)².(x² =[(x-1)²+9(x-y)².(x+y)²-6(x²-2x)+1 =(x²-2x)² (x-y)² -2x+1)² ]²-6x² 3; =[(x+y)-3(x-y)]² =(x+y)².(x²y²+y²-6(x+y)(x-y)+9(x-y)²)²-4（x+y)+4 =(x+y-2)²+2(x²)+9(x-y)² =(x-1)^4 4;-4x²+y² =(x۵