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

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

= -

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

with a = 1 and b = - 18, thus

= - = 9

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

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

Vertex = (9, - 1 )

(d)

step-by-step explanation:

given: the line in the graph passes through points (5,30) and (6,26).

then, the equation of line is:

now, put y=a(n) and x=n,

hence, option d is correct.