(m+15)+n = m + 15 + n
(m+48)+(n+20) = m + 48 + (n + 20) = m + 48 + n + 20 = m + 68 + n
m(n+9) = mn + 9m
(m+7)+n = m + 7 + n
(n+26)+(n+14)= n + 26 + (n + 14) = n + 26 + n + 14 = 2n + 40
(m+15)+n = m + 15 + n
(m+48)+(n+20) = m + 48 + (n + 20) = m + 48 + n + 20 = m + 68 + n
m(n+9) = mn + 9m
(m+7)+n = m + 7 + n
(n+26)+(n+14)= n + 26 + (n + 14) = n + 26 + n + 14 = 2n + 40