Question

What is the vertex of the parabola given by y = x2 − 10x + 17? A. (5, -8) B. (-5, 8) C. (5, 8) D. (-5, -8)

Answer 1

A

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 = x² - 10x + 17 ← is in standard form

with a = 1 and b = - 10, thus

`x_(vertex)` = -
`(-10)/(2)` = 5

Substitute x = 5 into the equation for corresponding value of y

y = 5² - 10(5) + 17 = 25 - 50 + 17 = - 8

vertex = (5, - 8 ) → A