The answer you are looking for is letter A, x=30.
Solution/Explanation:
First, write out the equation,
1200-5(3x+30)=600
Next, using the Distributive Property,
1200-15x-150=600
Simplify the left side of the equation just a little bit more,
1050-15x=600
Reverse order of terms on the left side, to make it a little bit easier to solve,
-15x+1050=600
Now, subtract 1050 from both sides,
-15x+1050-1050=600-1050
Now, simplify this part of the equation,
-15x=-450
Finally, divide both sides by -15,
So, therefore, the final answer is x=30.
I hope this helped you. Enjoy your day, and take care!