How are linear functions constructed, given a description of a relationship ?

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

What is the anwers for 9+2x=5x-3-x

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?