Ratio question

i have the answer, just that i don't fully understand how you get it,
can someone go through the whole process for me?
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3. solve the given inequality and graph the solution on a number line.

To find the extreme values of a function f(x.y) on a curve x-x(t), y y(t), treat f as a function of the single variable t and use the chain rule to find where df/dt is zero. in any other single-variable case, the extreme values of f are then found among the values at the critical points (points where df/dt is zero or fails to exist), and endpoints of the parameter domain. find the absolute maximum and minimum values of the following function on the given curves. use the parametric equations x=2cos t, y 2 sin t functions: curves: i) the semicircle x4,y20 i) the quarter circle x2+y-4, x20, y20 b, g(x,y)=xy

Iwant to know what 3g+5h+4g-2h is my teacher is too selfish to tell us