SOLUTION: I need to write the vertex form equation of the parabola with the given information: Opens up or down, Vertex (-10,3), passes through (-8,7) Can someone help me throught th

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: I need to write the vertex form equation of the parabola with the given information: Opens up or down, Vertex (-10,3), passes through (-8,7) Can someone help me throught th      Log On


   

Question 278971: I need to write the vertex form equation of the parabola with the given information:
Opens up or down, Vertex (-10,3), passes through (-8,7)
Can someone help me throught this step by step please?
Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
I need to write the vertex form equation of the parabola with the given information:
Opens up or down, Vertex (-10,3), passes through (-8,7)
Can someone help me throught this step by step please?

Start with the vertex form:

y=a%28x-h%29%5E2%2Bk

Substitute h=-10, k=3

y=a%28x-%28-10%29%29%5E2%2B%283%29

y=a%28x%2B10%29%5E2%2B3

You have it all but a

Next substitute the point that it passes through:

x=-8, y=7

7=a%28-8%2B10%29%5E2%2B3

7=a%282%5E2%29%2B3

7=a%284%29%2B3

7=4a%2B3

-4=4a

-1=a

Substitute a=-1in

y=a%28x%2B10%29%5E2%2B3

y=-1%28x%2B10%29%5E2%2B3

y=-%28x%2B10%29%5E2%2B3

That's it.

Edwin