Question

1. Find the vertex of y = – x2 - 4x + 5

Answer 1

Answer:

(- 2, 9 )

Step-by-step explanation:

Given a parabola in standard form, y = ax² + bx + c : a ≠ 0

Then the x- coordinate of the vertex is

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

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

with a = - 1 and b = - 4, thus

$x_{vertex}$ = - $\frac{-4}{-2}$ = - 2

Substitute x = - 2 into equation for corresponding y- coordinate

y = - (- 2)² - 4(- 2) + 5 = - 4 + 8 + 5 = 9

vertex = (- 2, 9 )