Question

Which is the vertex of x2 + 10x = -17 (-5,-8) (5,8) (-5,8) (5,-8)

Answer 1

Answer:

vertex = (- 5, - 8)

Step-by-step explanation:

Given a quadratic in standard form : ax² + bx + c = 0 : a ≠ 0

Then the x- coordinate of the vertex is

$x_{vertex}$ = - $\frac{b}{2a}$

Given x² + 10x = - 17 ( add 17 to both sides )

x² + 10x + 17 = 0 ← in standard form

with a = 1, b = 10, c = 17, then

$x_{vertex}$ = - $\frac{10}{2}$ = - 5

Substitute x = - 5 into the quadratic for the corresponding value of y

y = (- 5)² + 10(- 5) + 17 = 25 - 50 + 17 = - 8

Hence vertex = (- 5, - 8)