The Quadratic Function with a Constant, f(y) = 8y2 – 7y + 6, is an equation that can be written in the form of ax² + bx + c. The graph of this function is shown below: We notice from the graph that as y increases by 1 unit, the output value changes by 2 units on average. For example, when y = 3 and y = 4, then f(3) ≈ 9 and f(4) ≈ 16. This is because the graph of a quadratic function has the shape of a parabola. What does this mean for our Quadratic Function with Constant? This means that as x increases by one unit, then y also must increase by two units on average (or equivalently, when we calculate ƒ(x) = ax² + bx+c and plug in x=k to get f(k), then f’(k) ≈ -16). For example: if x = 0 and k ≠0, then ƒ(-0) = (-b/a)(-b ± sqrt((-b^²)/a)) is undefined but ƒ(0)=100