are quadratic functions one to one?
There are two values of x that give the y value 1 so the function is not one - to - one. f(x) is a parabola and a horizontal line can cut it twice. The function g(x) = x3 in example 7 is both one - to - one and onto. y values go from y = –∞ to y = ∞ and the function is increasing on all it's domain.