初一 数学 因式分解 请详细解答,谢谢! (1 21:38:7)4(3x+2y)^2-9(x-y)^2(要有过程)
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初一 数学 因式分解 请详细解答,谢谢! (1 21:38:7)4(3x+2y)^2-9(x-y)^2(要有过程)
初一 数学 因式分解 请详细解答,谢谢! (1 21:38:7)
4(3x+2y)^2-9(x-y)^2(要有过程)
初一 数学 因式分解 请详细解答,谢谢! (1 21:38:7)4(3x+2y)^2-9(x-y)^2(要有过程)
4(3x+2y)^2-9(x-y)^2
=2^2*(3x+2y)^2-3^2*(x-y)^2
=(6x+4y)^2-(3x-3y)^2
=[(6x+4y)+(3x-3y)][(6x+4y)-(3x-3y)]
=(9x+y)(3x-7y)
=[2(3x+2y)]^2-[3(X-Y)]^2
=(6x+4y+3x-3y)(6x+4y-3x+3y)
=(9x+y)(3x+7y)
4(3x+2y)^2-9(x-y)^2
=[2(3x+2y)+3(x-y)][2(3x+2y)-3(x-y)]平分差公式
=(9x+y)(3x+7y)
由于4是2的平方,9是3的平方,故原式可表示为:原式=[2(3x+2y)+9(x-y)]*[2(3x+2y)-3(x-y)]=(9x+y)*(3x+7y).
4(3x+2y)^2-9(x-y)^2
=4(9x²+4y²)-9(x²-y²)
=36x²+16y²-9x²+9y²
=27x²+25y²
最简形式
4(3x+2y)^2-9(x-y)^2
=[2(3x+2y)+3(x-y)][2(3x+2y)-3(x-y)]
平方差公式
=[2(3x+2y)]^2-[3(x-y)]^2
=(6x+4y)^2-(3x-3y)^2
=(6x+4y+3x-3y)(6x+4y-3x+3y)
=(9x+y)(3x+7y)