Divide the total amount charged by the number of hours worked, and you have $/hour
$168÷14 hours = $12/hour
Recall that the vertex form of a quadratic function (or parabolic function) is equal to

Now, given that we have f(x) = x² + 14x + 40, to express f into its vertex form, we must first fill in the expression to form a perfect square.
One concept that we must remember when completing the square is that
(a + b)² = a² + 2ab + b²
So, to complete the square for (x² + 14x + ____), we have 2ab = 14 where a = 1. Thus, b = 14/2 = 7. Hence, the last term of the perfect square must equal to 7² = 49.
So, going back to the function, we have




Thus, we have derived the vertex form of the function.
Answer: f(x) = (x + 7)² - 9
Step-by-step explanation:


Given: ax-by>c
Subtract ax on both sides: -by>-ax+c
Divide both sides by -b: y<(-ax+c)/-b
Simplify: y<(ax-c)/b
your answer: y<(ax-c)/b
Plug in -1 for x and work it ou'
g(-1) = (-1)^3 + 6(-1)^2 + 12(-1) + 8
= -1 + 6 - 12 + 8
= 1