Question

Where is the vertex of the equation?y = x2 – 18x + 80

Answer 1

Answer:

vertex = (9, - 1 )

Step-by-step explanation:

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

Then the x- coordinate of the vertex is

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

y = x² - 18x + 80 ← is in standard form

with a = 1 and b = - 18, thus

$x_{vertex}$ = - $\frac{-18}{2}$ = 9

Substitute x = 9 into the function for corresponding value of y

y = 9² - 18(9) + 80 = 81 - 162 + 80 = - 1

Vertex = (9, - 1 )