Question

(n+2)(n+5)-(n-1)(n-10)

Answer 1

(n+2)(n+5)-(n-1)(n-10)=n^2+5n+2n+10-n^2+10n+n-10 = 18n

Answer 2

(n^2+5n+2n+10)-(n^2-10n-1n+10)= n^2+5n+2n+10 - n^2+10n+1n-10= 7n+11n=18n