For this problem, I'd use cross-multiplication.
9/12 = x/8.
When cross multiplying, multiply 12*x and 9*8. This leads to a new equation:
12x = 72.
Then you solve as an algebra problem.
*Divide 12 on both sides*
x = 6.
Answer:
Jade paid more per gallon than Carly
Step-by-step explanation:
7x + 2y = 48
7x + (2x3) =48
7x + 6 = 48
7x = 48 - 6
7x = 42
--> x = 6