How do you do this maybe you learn or do something how do you understand x and y

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

What are the values of each variable in the diagram below?

Onnie is considering doing some long term investing with money that she inherited. she would like to have $50,000 at the end of 30 years. approximately how much money would lonnie need to put into an account earning 6% interest compounded annually in order to meet her goal?