Answer: -12/4
Step-by-step explanation: first you substitute in your unknowns (-3/4 in for a and 1/2 in for b) then you multiply -3/4 by two. Then devide by 1/2 (if you don't know how to do that you take the recipicle of the fraction you are dividing by so in this case 1/2 becomes 2/1 and multiply the two instead of deviding.
