Question

What is the vertex of this parabola? y= 2x² + 4x +5

Answer 1

vertex = (- 1, 3 )

Explanation:

Given a parabola in standard form

y = ax² + bx + c ( a ≠ 0 )

Then the x- coordinate of the vertex is

`x_(vertex)` = -
`(b)/(2a)`

y = 2x² + 4x + 5 ← is in standard form

with a = 2, b = 4, then

`x_(vertex)` = -
`(4)/(4)` = - 1

Substitute x = - 1 into the equation for corresponding value of y, that is

y = 2(- 1)² + 4(- 1) + 5 = 2 - 4 + 5 = 3

vertex = (- 1, 3 )