Question

two angles are complementary. their difference is 4. find the angles

Answer 1

you are basically confronted with a system of equations.
lets name the two angles x and z. (no matter which one is which).

you know that they are complementary
and the definition of complementary angles, lets say x and z are complementary, is that
So, you know that
\(\large\color{black}{ x+z=90 }\)
and you know that the difference between them is 4, so
\(\large\color{black}{ x-4=z }\)