因式分解 (1) 4(2x+y)^2-9(x+2y)^2 (2) (x+y)(x+y-2)+1 /

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因式分解 (1) 4(2x+y)^2-9(x+2y)^2 (2) (x+y)(x+y-2)+1 /
因式分解 (1) 4(2x+y)^2-9(x+2y)^2 (2) (x+y)(x+y-2)+1 /

因式分解 (1) 4(2x+y)^2-9(x+2y)^2 (2) (x+y)(x+y-2)+1 /
韩小婧3:
(1)4(2x+y)²-9(x+2y)²
=[2(2x+y)]²-[3(x+2y)]²
=(4x+2y)²-(3x+6y)²
=(4x+2y+3x+6y)(4x+2y-3x-6y)
=(7x+8y)(x-4y)
(2)(x+y)(x+y-2)+1
=(x+y)[(x+y)-2]+1
=(x+y)²-2(x+y)+1
=(x+y-1)²

4(2x+y)^2-9(x+2y)^2 =4(4X^2+Y^2+4XY)-9(X^2+4Y^2+4XY)=16X^2+4Y^2+16XY-9X^2-36Y^2-36XY=7X^-32Y^2-20XY