SOLUTION: Find the x intercepts of the parabola with vertex (-5,80) and y intercept (0,-45). Round to the nearest hundredth

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Question 924695: Find the x intercepts of the parabola with vertex (-5,80) and y intercept (0,-45). Round to the nearest hundredth
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Parabola using only TWO given points?


y=a%28x-r%29%28x-s%29

Using s=-45
y=a%28x-r%29%28x-%28-45%29%29
y=a%28x-r%29%28x%2B45%29

highlight_green%28a%28x-r%29=y%2F%28x%2B45%29%29.............

Two points alone will not define a parabola. You could allow a to be any value you want, as long as highlight_green%28a%3C%3E0%29; and then you can substitute for (-5,80) and solve for "r", the other root.

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
Find the x intercepts of the parabola with vertex (-5,80) and y intercept (0,-45). Round to the nearest hundredth 


In the vertex form of a parabolic equation: y+=+a%28x+-+h%29%5E2+%2B+k, substitute coordinates of vertex,

and y-intercept point to determine "a."

Then solve for x: the roots or the zeroes of the parabola.

You should get:  x = - 1.151 ≈ highlight_green%28x+=+-+1.15%29  	OR            x = - 8.849 ≈ highlight_green%28-+8.85%29

Then do a check!! 

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