Answer:
The correct answer is 12.
Step-by-step explanation:
To solve this problem, we must plug in 3 for each occurrence of y in the expression because we are given that y = 3. In this case, we will get the following:
7y - 3y
7(3) - 3(3)
To evaluate, we must simplify this expression. Due to the order of operations, we should compute the multiplication first. 7*3 = 21 and 3*3=9, so we can plug in these values into our expression.
21 - 9
Now, we can perform the subtraction.
21-9=12
Therefore, the correct answer is 12.
Hope this helps!