解:(x^m/x^2n)^3/x^(m-n)与4x^2为同类项即3(m-2n)-(m-n)=23m-6n-m+n=22m-5n=2所以2m-5n-7=2-7=-5为你解答,如有帮助请采纳,如对本题有疑问可追问,Good luck!