[(x+2y)(x-2y)-(2x-y)^2+(3x-y)(2x-5y)]/(-1/2x)
问题描述：
[(x+2y)(x-2y)-(2x-y)^2+(3x-y)(2x-5y)]/(-1/2x)
79*3.14+10*1.34+11*1.34
答
肯定对哦[(x+2y)(x-2y)-(2x-y)^2+(3x-y)(2x-5y)]/(-1/2x) =[(x^2-4y^2)-(4x^2-4xy+y^2)+(6x^2-17xy+5y^2)]/(-1/2x)=(x^2-4y^2-4x^2-y^2+6x^2-17xy+5y^2)/(-1/2x)=(3x^2-13xy)/(-1/2x)=-6x+26y79*3.14+10*1.34+11*1.3...