Question

2. The graph of the equation y = x2 + 2x – 8 has a minimum at (x,-9).Part A: What is the value of x ?Part B: What is the y-intercept?Part C: Make a table & graph thefunction.

Answer 1

Problem

Solution

Part A

For this case we can do this:

`-9=x^2+2x-8`

And solving for x we got:

`-1=x^2+2x=x(x+2)`

Then the possible solutions for this case is x= -1

Part B

For this case we can do the following:

`0=x^2+2x-8`

And if we factorize we got:

`0=(x+4)(x-2)`

And the x intercepts are:

x=-4 and x=2

And the y intercept is just (0,-8)

Part C

For this case we can do the following:

x y

-4 0

-3 -5

-2 -8

-1 -9

0 -8

1 -5

2 0

3 7

4 16

and the graph would be given by: