已知|m-n-2|与(mn-1）的2次方互为相反数,求(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)
问题描述：
已知|m-n-2|与(mn-1）的2次方互为相反数,求(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)
答
因为|m-n-2|大于等于0 (mn-1）的2次方大于等于0且|m-n-2|与(mn-1）的2次方互为相反数所以m-n-2=0 mn-1=0则m-n=2 mn=1(-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=-6mn+3m-3n=3(-2mn+m-n)将m-n=2 mn=1代入,得原式=3*（-2*1+2...