13. Find the vertex of f(x)=x2 -6x +8 . a
(3,-1)

b
(-3, 1)

c
(-3,-1)

d
(3, 1)

9514 1404 393

  a  (3,-1)

Step-by-step explanation:

The number that "completes the square" is the square of half the x-coefficient, (-6/2)^2 = 9. Rearranging the given function to include the square trinomial, we have ...

  f(x) = x^2 -6x +9 -1 . . . . . . . here, we have 8 = 9 - 1

  f(x) = (x -3)^2 -1 . . . . . . . . . . vertex form

Comparing this to the generic vertex form ...

  f(x) = (x -h)^2 +k . . . . . . . vertex at (h, k)

we see that h=3 and k=-1.

The vertex is (h, k) = (3, -1).

y = - 6

step-by-step explanation:

given the point (- 2, y) lies on the graph then it is a solution of it's equation.

substitute x = - 2 into the equation for value of y

y = 3(- 2) = 3 × - 2 = - 6

the point on the graph is (- 2, 6)

the answer is c

step-by-step explanation: