-$70 is her balance after withdrawing the forty dollars
"x" always goes on the left side and "y" always goes on the right side of the parentheses. If you only have an "x" then you will just put a zero in for "y" and vice versa. I hope this helps.
C because if you divide 3/12 you get .25 but 4/18 is .22, which is the better deal
