Question

What are the vertex and x-intercepts of the graph of the function given below?

Answer 1

Answer:

D. Vertex: (1, –49); x-intercepts: (8, 0) and (–6, 0)

Answer 2

VERTEX
To determine the vertex (coordinate x) of parabola y = ax² + bx + c, use this following formula
x vertex = $-\dfrac{b}{2a}$

y = x² - 2x - 48
a = 1, b = -2, c = -48
plug in the numbers
x vertex = $-\dfrac{b}{2a}$
x vertex =  $-\dfrac{(-2)}{2(1)}$
x vertex =  $\dfrac{2}{2}$
x vertex = 1

To find y vertex, substitute the value of x vertex to the parabola equation
y = x² - 2x - 48
y = 1² - 2(1) - 48
y = 1 - 2 - 48
y = -49

The vertex is (1, -49)

X-INTERCEPT
x-intercept located in x axis, that means y = 0. Substitute y = 0 to the parabola equation
x² - 2x - 48 = y
x² - 2x - 48 = 0
(x - 8)(x + 6) = 0
x = 8 or x = -6
The x-intercepts are (8,0) and (-6,0)

The answer is first option