Chapter 15 Review

Here is a copy of the Chapter 15 Test review.  All material for the chapter has been covered and nothing further will be added.

Here is the key to the review.  

Remember you can find the vertex by either completing the square or using -b/2a to find the x coordinate.  You find the y coordinate by plugging in the x value to the equation.

For interval of increase and decrease, follow the following.

Quadratic function: f(x) = ax² + bx + c 

First we find x-coordinate for vertex: x = -b/(2a) 

If a < 0, then we have a parabola that opens down 

So  the vertex is a maximum point 

Function increases on interval (-∞, -b/(2a)) 

Function decreases on interval (-b/(2a), ∞) 

If a > 0, then we have a parabola that opens up 

So the vertex is a minimum point 

Function decreases on interval (-∞, -b/(2a)) 

Function increases on interval (-b/(2a), ∞)

Remember you can find the vertex by doing -b/2a to find the x coordiante.  Then 

plug in the x value to find the corresponding y value.  Your axis of symmetery is 

x=-b/2a.