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a^2-8ab+16b^2+6a-24b+9和(x+2y)(3x-7y)^2-4(x+2y)(x+y)^2因式分解

题目详情
a^2-8ab+16b^2+6a-24b+9和(x+2y)(3x-7y)^2-4(x+2y)(x+y)^2
因式分解
▼优质解答
答案和解析
a^2-8ab+16b^2+6a-24b+9
=(a-4b)²+6(a-4b)+9
=(a-4b+3)²
(x+2y)(3x-7y)^2-4(x+2y)(x+y)^2
=(x+2y)((3x-7y)²-4(x+y)²)
=(x+2y)(2x-7y+2(x+y))((2x-7y)-2(x+y))
=(x+2y)(4x-5y)(-9y)
=-9y(x+2y)(4x-5y)