Which relation is a function?

What does x = in this equation x+3+2x=x+5

The revenue each season from tickets at the theme park is represented by t(c)=5x. the cost to pay the employees each season is represented by r(x)=(1.5)^x. examine the graph of the combined function for total profit and estimate the profit after four seasons

The measure of an angle is 117°. what is the measure of a supplementary angle?