I hope this helps you
[20x^2/4x^2y]+[4xy^2/4x^2y]-[8y^2/4x^2y]
[5/y]+[y]-[4y/x^2]
Supplementary Angles:

Arithmetically speaking, the closest 2 supplementary angles can get (in 3 and 2 digits respectively) is the upwritten.
Complementary Angles:

Simply, in this case, for angles to be numerically as close as possible - make both the angles 45°.
H + 121 + 31 = 180
H + 152 = 180
H = 180 - 152
H = 28
1) factor to see if you can get anything to cancel out before you multiply
2) the rest of my work is shown in the picture attached
3) the answer is n^2