25(x+y)²-9(x-y)²
=[5(x+y)]²-[3(x-y)]²
=[5(x+y)+3(x-y)][5(x+y)-3(x-y)]
=(8x+2y)(2x+8y)
=4(4x+y)(x+4y)
25(x加y)的平方减9(x减y)的平方因式分解
25(x+y)²-9(x-y)²
=[5(x+y)]²-[3(x-y)]²
=[5(x+y)+3(x-y)][5(x+y)-3(x-y)]
=(8x+2y)(2x+8y)
=4(4x+y)(x+4y)