(4M-n)(4m+n)-(2m+n)^2

Question

(4M-n)(4m+n)-(2m+n)^2

Answer 1

16m^2 - n^2 -(4m^2 + 4mn + n^2) = 16m^2 - n^2 - 4m^2 - 4mn - n^2 = 12m^2 - 2 n^2 - 4mn