Answer :
m x m = m ^ 2
m x 3 = 3m
-6 x m = -6m
-6 x 3 = -18
adding these you get m^2 -3m -18
m x 3 = 3m
-6 x m = -6m
-6 x 3 = -18
adding these you get m^2 -3m -18