how do i find the axis of symmetry of -7 and 1

Question

 i need help finding the axis of symmetry when the quadratic equation is -7 and 1

Answer 1

Hi Sav, the axis of symmetry for a quadratic equation is: -b / 2a, where a and b come from ax² + bx + c = 0.

 

Start with the two values, -7 and 1. Set these values equal to x.

 

x = -7,     x = 1

 

Add 7 to both sides of the first equation and -1 to both sides of the second equation giving:

 

x + 7 = 0, and x - 1 = 0

 

This gives:

 

(x + 7) * (x - 1) = 0

 

Multiply the to binomials giving:

 

x² + 6x - 7 = 0

 

Using: -b / 2a gives: -6 / 2 = -3

 

The axis of symmetry is -3.

 

Questions?

Answer 2

This is a bit unclear. Do you mean the x-intercepts are -7 and 1? If yes, the axis of symmetry would be the vertical line midway between them. Since (-7+1)/2 = -3, the axis of symmetry would have equation x = -3.

 

If you meant something else, be sure to post a reply so someone can help with it.