5m的二次方-[5m的二次方-(2m的平方-mn)-7mn]-5
=5m的2次方-5m的2次方+2m的2次方-mn+7mn-5
=2m的2次方+6mn-5
=2(m的2次方+3m)-5
=2x5-5
=5
如果本题有什么不明白可以追问,如果满意请点击“好评”
5m的二次方-[5m的二次方-(2m的平方-mn)-7mn]-5
=5m的2次方-5m的2次方+2m的2次方-mn+7mn-5
=2m的2次方+6mn-5
=2(m的2次方+3m)-5
=2x5-5
=5
如果本题有什么不明白可以追问,如果满意请点击“好评”