Algebra Thing

In a quintic function: as f(x) approaches negative infinity x approaches positive infinity, f(x) approaches postive infinity as x approaches ______________________

If Brynn sell PB and Js for 5 dollars each (them better have some quality peanut butter), what is the independant variable?

Is this equation a polynomial in one variable? If so, what is the degree?: y= x cubed plus 7 squared