x(a-1)(a-2)-y(1-a)(2-a)
=x(a-1)(a-2)-y(a-1)(a-2)
=（a-1)(a-2)(x-y)
4(x+y)2-9(2x-3y)2
=[2(x+y)]² - [3(2x-3y)]²
=(2x+2y+6x-9y)(2x+2y-6x+9y)
=(8x-7y)(11y-4x)
同学你好,如果问题已解决,记得右上角采纳哦~~~您的采纳是对我的肯定~谢谢哦