THE ANSWER IS 24
A and b are in parenthesis and there is no sign next to them, so you automatically have to multiply.
If that is supposed to be ab^2 then:
First you multiply 4 and 3 to get 12.
Then you multiply 12 by itself to get 144.
If it is supposed to be 2ab then:
First multiply 4 and 3 to get 12.
Then multiply 12 and 2 to get 24.
