Question

Find the vertex of the parabola whose equation is y=-2x2+8x-5

Answer 1

Given equation is
`y= 2x^2 + 8x - 5`

To find the x coordinate of vertex we use formula

`x=(-b)/(2a)`

From the given equation a= 2, b= 8 and c= -5

Plug in all the values

`x=(-8)/(2*2)=-2`

The x coordinate of vertex is x=-2

To find y coordinate of vertex we plug in -2 for x in the given equation

`y= 2x^2 + 8x - 5`

`y= 2(-2)^2 + 8(-2) - 5= 8-16-5=-13`

So vertex is (-2,-13)