Can someone explain long division to me?

Create a real-life situation and create a system and show how it might be modeled algebraically with a system of equations (or inequalities) show all work include a few sentences explaining the situation, your variables of choice and what each represents, and how you would set it up and solve it algebraically. !

What signals you that factoring by grouping is the best method to use when factoring a problem?

Given f(x)= 9x+1 and g(x)=x^3, choose the expression (f*g)(x)