Question

Which table contains the vertex of the graph represented by y=x^2-6x+4?

Answer 1

vertex = (3,- 5 )

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 - 6x + 4 is in standard form

with a = 1, b = - 6 and c = 4, hence

$x_{vertex}$ = - $\frac{-6}{2}$ = 3

substitute this value into the equation for y- coordinate

y = 3² - 6(3) + 4 = 9 - 18 + 4 = - 5

vertex = (3, - 5 ) → second table