If "x" is the degree measure of the given angle, then the measure of its complement is (x-50) degrees.
And since these angles are complementary, you have this equation
x + (x-50) = 90 degrees.
It implies
2x - 50 = 90 ====> 2x = 90 + 50 = 140 ====> x = = 70 degrees.
Answer. The given angle is 70 degrees. Its complement is 90-70 = 20 degrees.
Check. 70 - 20 = 50 degrees, exactly as the condition states. ! Correct !