The first step for solving this equation is to move the constant to the right side by adding its opposite to both sides.
x + 7.5 - 7.5 = 28.5 - 7.5
Now eliminate the opposites.
x = 28.5 - 7.5
Lastly,, subtract the numbers on the right to find your final answer.
x = 21
This means that the correct answer to your question is going to be options B.
Let me know if you have any further questions.
:)
