For which pairs of functions does (f*g)(x)=x?

5.(04.07) two different plants grow each year at different rates, which are represented by the functions f(x) = 4* and g(x) = 5x + 2. what is the first year the f(x) height is greater than the g(x) height? year 3 year 0 year 2 year 1

Ineed to know the answer to this algebra question.

What is the measure of sty in oo below? 130 310 230 50