因式分解9（x-y）²+12（x²-y²）+4（x+y）²

因式分解9（x-y）²+12（x²-y²）+4（x+y）²
因式分解9（x-y）²+12（x²-y²）+4（x+y）²

因式分解9（x-y）²+12（x²-y²）+4（x+y）²
原式=[3(x-y)]²+12(x+y)(x-y)+[2(x+y)]²
=[3(x-y)+2(x+y)]²
=(5x-y)²

9（x-y）²+12（x²-y²）+4（x+y）²
=9x^2+9y²-18xy+12x²-12y²+4x^2+4y²+8xy
=25x^2+y^2-10xy
=（5x-y）^2