+0  
 
0
43
1
avatar

The vertex of this parabola is at (2, -1). When the y-value is 0, the x-value is 5.   What is the equation of the parabola?

 Feb 27, 2020
 #1
avatar+18835 
0

A formula for a parabola is:  y - k  =  a(x - h)2

where (h, k) are the coordinates of the vertex.

Since the vertex is at (2,-1),  h = 2   and  k = -1.

Putting those values into the formula:  y - -1  =  a(x - 2)2  or  y + 1  =  a(x - 2)2

To find the value of a, substitute these values:  y = 0  and  x = 5  into the equation.

     0 + 1  =  a(5 - 2)2

            1  =  a(3)2

            1  =  9a

            a  =  1/9

The equation is:  y + 1  =  (1/9)(x - 2)2

 Feb 27, 2020

37 Online Users

avatar
avatar
avatar
avatar
avatar
avatar
avatar