multiplying polynomials
(3m-1)(8m+7)
\((3m-1)(8m+7)=3m\cdot 8m+3m\cdot 7-1\cdot 8m-1\cdot 7=\\ \\=24m^2+21m-8m-7=24m^2+13m-7\)
(3m -1)(8m + 7)= {3m(8m + 7)} - {1(8m+7)}= 24m² + 21m - 8m+ 7= 24m² + 13m - 7
