Which statements are true about the graph of the function f (x) = x2 - 8x + 5? Check all that apply. The function in vertex form is f (x) = (x - 4) 2 - 11. The vertex of the function is (-8, 5). The axis of symmetry is x = 5. The y-intercept of the function is (0, 5). The function crosses the x-axis twice.

Question

Mathematics

Giovanny

2 November, 23:16

Which statements are true about the graph of the function f (x) = x2 - 8x + 5? Check all that apply. The function in vertex form is f (x) = (x - 4) 2 - 11. The vertex of the function is (-8, 5). The axis of symmetry is x = 5. The y-intercept of the function is (0, 5). The function crosses the x-axis twice.

+5

Answers (1)

Know the Answer?

Tamara Garcia · Answer 1

The function in vertex form part is correct. You find this by completing the square. The vertex, then, would be (4, - 11), so that part is incorrect. The axis of symmetry is the same as the x coordinate of the vertex, so that part is incorrect also, because the axis of symmetry is x = 4. The y-intercept exists where x = 0, so replace all the x's with 0's and get that y = 5, so the y-intercept part is correct. It does cross the x axis in 2 places, once at 4+square root 11 and once at 4-square root 11, which in real numbers is x = 10.6332 and x = - 2.6332