(2x-y)(y+2x)-(2y+x)(2y-x),且X+Y=5,X-Y=3

题目

(2x-y)(y+2x)-(2y+x)(2y-x),且X+Y=5,X-Y=3
赶时间

答案

(2x-y)(y+2x)-(2y+x)(2y-x)
=(2x-y)(2x+y)-(2y+x)(2y-x)
=4x^2-y^2-4y^2+x^2
=5(x^2-y^2)
=5(x+y)(x-y)
=5*5*3
=75