Question

Find the x-intercept(s) and the coordinates of the vertex for the parabola.

Answer 1

see explanation

Explanation:

Given

y = x² - 2x - 8

To find the x- intercepts let y = 0 , that is

x² - 2x - 8 = 0 ← in standard form

(x - 4)(x + 2) = 0 ← in factored form

Equate each factor to zero and solve for x

x - 4 = 0 ⇒ x = 4

x + 2 = 0 ⇒ x = - 2

x- intercepts : x = - 2, x = 4

The x- coordinate of the vertex is mid way between the x- intercepts, that is

`x_(vertex)` =
`(-2+4)/(2)` =
`(2)/(2)` = 1

Substitute x = 1 into the equation for corresponding y- coordinate

y = 1² - 2(1) - 8 = 1 - 2 - 8 = - 9

vertex = (1, - 9 )