Question

f(x)=x2−2x−8.
please tell by step​

Answer 1

Answer:

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Step-by-step explanation:

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Answer 2

Given,

$\bold{f(x)=x^2−2x−8}$

to find the vertex, we know,

$\bold{x = - \frac{b}{2a} = - \frac{ - 2}{2 \times 1} = 1}$

to find y coordinate, substitute the value of x in equation.

$\bold{(1)^2−2(1)−8=1−2−8=9}$

$\bold{x^2−2x−8=0}$

(x−4)(x+2)=0

x=−2,4

The x intercepts are (−2,0),(4,0)

To find the y intercept, substitute x=0 in given equation,

The vertex is (1,9)

Now, x intercepts,

$\bold{x^2 −2x−8=0}$

(x−4)(x+2)=0

x=−2,4

The x intercepts are (−2,0),(4,0)

To find the y intercept, substitute x=0 in given equation,

$\bold{0^2−2(0)−8=−8}$

The y intercept is (0,−8)

Thus it is an upward facing parabola, touching x and y axis at (2,−8),(−1,−5),(3,−5)