Answer:
3. Simplifying
4 multiplication property of equality.
5. simplifying
Explanation:
y/2 -21+21 = -15+21
To get to the next step we add -21+21 on the left and -15+21 on the right
We are simplifying on each side
Then we multiply by 2 on each side for the next step
We use the multiplication property of equality.
Finally we simplify in the last step