What is the greatest common factors of 20,40,50 and 120

The functions f(x) and g(x) are shown in the graph f(x)=x^2 what is g(x) ?

Jessica is organizing a guided tour of the rain forest. the average profit per person that the touring company makes is given by the rational expression 18x+35/x, where x is the number of people going on the tour. what does the numerator of this rational expression represents?

Can anyone explain to me how to do this? anything will .