If e=5t where y represents the earnings from t t-shirts sold is it proportional why or why not?

Can someone explain the elimination method to me for this problem?

Use the inverse of the function y=x^2-18x to find the unknown value [tex]y = \sqrt{bx + c \: + d} [/tex]

(08.01)consider the following pair of equations: x + y = −2 y = 2x + 10 if the two equations are graphed, at what point do the lines representing the two equations intersect? (−4, 2) (4, 2) (−2, 4) (2, 4)