Given:
Trevor solved the system of equations below.
Trevor made the following steps to solve the system of equations:
y = 5 − 2x ⇒ correct
x − 2(5 − 2x) = 10 ⇒ correct
x − 10 + 4x = 10 ⇒ correct
5x − 10 = 10 ⇒ Wrong
5x = 0
x = 0
So, the fourth step is wrong, because he subtracted 10 from both sides
And the correct should be adding 10 to both sides
so, the answer will be option C.
c. He subtracted 10 from the right side instead of adding 10 to the right side