The answer is y = 2/3x - 22/3
Example: Set up proportions.
3/4 cups → 1 batch
x cups → 2 batches
x = 2(3/4) = 6/4 = 1 1/2 cups
3/4 cups → 1 batch
y cups → 9 batches
y = 9(3/4) = 6 3/4 cups
If you factor it then your answer will be -3(-3z-5) if you simplify the answer is 9z+15