Question

For 7 and 8, find the maximum or minimum point of the parabola​

Answer 1

Answer: 7) Max: y = 52

               8) Min: y = -51  

Step-by-step explanation:

The Max/Min is the y-value of the intercept.

• Max is when the a-value is negative.
• Min is when the a-value is positive.

First, find the x-value of the vertex using the Axis of Symmetry formula:

x = -b/2a. Then plug the x-value into the equation to find the y-value.

7) y = -2x² - 16x + 20

          ↓       ↓       ↓

     a= -2   b= -16  c=20

$\text{AOS:}\quad x=\dfrac{-b}{2a}\quad =\dfrac{-(-16)}{2(-2)}\quad =\dfrac{16}{-4}\quad =-4$

Max: y = -2(-4)² - 16(-4) + 20

           = -2(16) + 64 + 20

           = -32 + 84

          = 52

*********************************************************************************************

7) y = x² + 12x - 15

        ↓      ↓      ↓

   a= 1   b= 12  c= -15

$\text{AOS:}\quad x=\dfrac{-b}{2a}\quad =\dfrac{-(12)}{2(1)}\quad =\dfrac{-12}{2}\quad =-6$

Max: y = (-6)² + 12(-6) - 15

           = 36 - 72 - 15

           = 36 - 87

          = -51