-5(5x+y)-3(2x-3y)怎么做?

(2x+3y)(x-4y)、(5x-y)(-x-3y)、(3-x)(4+y)谁告诉我这类题怎么做呀? (y-x)(x-y)^3(y-x)^5怎么算 -5(5x+y)-3(2x-3y)怎么做? (2x-3y)-(5x-y)怎么算 (2x-3y)2-(4y-3x)(3x+4y)怎么做? [(3x+y)²-(3x-y)²]÷(4x-2y)计算 怎么做? 数学(x-y)^5*(y-x)^3*(x-y)^2 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) (2X-3y)-(5x-y) x=4-5y,3x-9y=4用代入法怎么做 x^4-2x^2y-3y^2+6y-4因式分解怎么做 y=3x平方+2x怎么做啊