SOLUTION: find vertex of the parabola y=x^2-8x-5 vertex (?,?)

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Question 212980: find vertex of the parabola
y=x^2-8x-5
vertex (?,?)
Answer by drj(1380) About Me  (Show Source):
You can put this solution on YOUR website!
Find the vertex of the parabola

y=x%5E2-8x-5

vertex (?,?)

Let's graph this parabola:


Try this set of x=-2, -1, 0, 1, 2 and substitute into parabola equation.

For example, x=-2, y=(-2)^2-8(-2)-5= 4+16-5=15 point on graph is (-2,15)

One more and then you try, x=0, y=(0)^2-8(0)-5=-5 point on graph is (0,5)

graph%28+300%2C+300%2C+-10%2C+10%2C+-25%2C+20%2Cy=x%5E2-8x-5+%29

Based on the graph the vertex is (4, -21)

Note when we substitute x=4 in

y=x%5E2-8x-5

y=4%5E2-8%284%29-5=16-32-5=-21

I hope the above steps were helpful.

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Good luck in your studies!

Respectfully,
Dr J