How do i solve more complicated equations e. g
3 (4a x3) = 4

3 (4a × 3) = 4     :First, distribute (Multiply the 3 times the 4a and the other 3)

12a × 9 = 4         :Then, divide the whole equation by 9

12a = 4/9             :Then, divide the whole equation by 12

a = 1/27          

(At least, that what I hoped your equation said at the beginning xD)

The correct answer will be d. -4

X= 2 he can buy 2 packs of cards for $12 and an action figure for $3 so he would spend $15 in total plus the free poster