Question

分解因式9(x+y)2-(x-y)2

初二数学

Answer 1

9(x+y)²-(x-y)²
=[3(x+y)]²-(x-y)²
=[3(x+y)+(x-y)][3(x+y)-(x-y)]
=(4x+2y)(2x+4y)
=4(2x+y)(x+2y)

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Answer 2

9(x+y)²-(x-y)²
=9（x²+2xy+y²）-（x²+2xy+y²）
=9x²+18xy+9y²+x²-2xy-y²
=10x²+16xy-8y²

Answer 3

9(x+y)2-(x-y)2
=[3(x+y)-(x-y)][3(x+y)+(x-y)]
=(2x+4y)(4x+2y)
=4(x+2y)(2x+y)

Answer 4

9(x+y)2-(x-y)2=(3x+3y)2-(x-y)2=(4x+2y)(2x+4y)=4(2x+y)(x+2y)