Answer is x .= 70
Step by step
The two angles will equal 180 degrees as a complementary angle.
So your equation is
2x + 40 = 180
Solve for x
Subtract 40 from both sides to isolate x
2x + 40 - 40 = 180 - 40
2x = 140
Divide both sides by 2 to solve for x
2/2 x = 140/2
x = 70
Now check your work
2x + 40 = 180
2 (70) + 40 = 180
140 + 40 = 180
180 = 180
Problem solved!