哭求个位高手了5555555

题目

哭求个位高手了5555555
填空：(-a^m)^2+(4a^ m+2 )(-a^ m-2 )=()

答案

原式=a^2m-4a^2m-2a^m-8a^m-4
=-3a^2m-10a^m-4