I used the FOIL method First outer inner last
I multiplied the first variables together (3a*4a) and got 12a^2
So just do what common sense tells you to do
Multiply the first parts of the quantities, the outer parts of the quantities, the inner parts of the quantities and the last parts of the quantities to get
12a^2+3a+12a+ 3
Then group it together
[tex] 12a^{2} + 15a + 3[/tex]
