因式分解：9(x-y)²-25(x+y)²因式分解：9(x-y)²-25(x+y)²

因式分解：9(x-y)²-25(x+y)²因式分解：9(x-y)²-25(x+y)²
因式分解：9(x-y)²-25(x+y)²
因式分解：
9(x-y)²-25(x+y)²

因式分解：9(x-y)²-25(x+y)²因式分解：9(x-y)²-25(x+y)²
9(x-y)²-25(x+y)²
=[3(x-y)]²-[5(x+y)]²
=(3x-3y-5x-5y)(3x-3y+5x+5y)
=(-2x-8y)(8x+2y)
=-4(x+4y)(4x+y)