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)=(8x+2y)(2x+8y)　　=4(4x+y)(x+4y)我感觉应该等于=2(4x+y)(x+4y)(8x+2y)(2x+8y)　　=[2(4x+y)]×[2(x+4y)]　　=2(4x+y)×2×(x+4y)　　=4(4x+y)(x+4y)