Collect the like terms
9x-5x=20
4x=20 divide both sided by 4
x=5
As you can see, in the table of the first function, f(2) = 18, and in the table of the second function g(2) = 18. Then, for x = 2, f(x) = g(x). and x =2 is the solution of the equation.
Answer: x = 2.
