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Algebra 2 - Vertex of a Function

by Jeimy
(Hollywood, FL)











































Find the vertex of the function. Write your answer in the form (x,y). Use the slash mark ( / ) as a fraction bar if necessary. y=x^2-5x-15

Comments for Algebra 2 - Vertex of a Function

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Nov 01, 2011
Vertex of a Parabola
by: Staff


Question:

by Jeimy
(Hollywood, FL)



Find the vertex of the function. Write your answer in the form (x,y). Use the slash mark ( / ) as a fraction bar if necessary. y = x^2 - 5x - 15



Answer:

y = x² - 5x - 15

this equation is the equation for a parabola

the general form of a parabola is:

y = ax² + bx + x

the quadratic formula is:

x = (-b/2a) ± [√(b² - 4ac)/2a]

the x coordinate of the vertex of the parabola is:

x_vertex = (-b/2a)

for your equation:

a = 1

b = -5

x_vertex = -(-5)/(2*1)

x_vertex = 5/2

x_vertex = 2.5


now that you know the x coordinate of the vertex, substitute this value in the original equation to compute y

y = x² - 5x - 15

x = 2.5

y = (2.5)² - 5 * 2.5 - 15
y = 6.25 - 12.5 - 15

y = -21.25

the coordinates of the vertex in x,y format are: (2.5, -21.25)


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http://www.solving-math-problems.com/images/graph-vertex-parabola-2011-10-31.png





Thanks for writing.

Staff
www.solving-math-problems.com


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