x+y-(2x-y)(x+y)=?12(a^2-b^2)^2-3(a^2+b^2)(a+b)^2等于多少(2a-b)(2

x+y-(2x-y)(x+y)=(x+y)(1-2x+y)
12(a^2-b^2)^2-3(a^2+b^2)(a+b)^2=12(a+b)²(a-b)²-3(a²+b²)(a+b)²=3(a+b)²(3a²-8ab+3b²)
(2a-b)(2a+3b)+3a(b-2a)=-(2a-b)(-a+3b),
a(x-3)(5-x)+b(3-x)(x-5)=(5-x)(x-3)(a+b)
代数式15x^3y^3(x-y),6x^2y^2(y-x),-120x^3y^3（x-y）（x+y）的公因式是3x²y²(x-y)
a-b+k(b-a)=(b-a)(k-1)
a(b-c)+c-b=(b-c)(a-1)
m(a-b)(a-c)-n(b-a)(c-a)=(a-b)(a-c)(m-n)