SOLUTION: it says, "Sketch the graphs, using the function and three points: two roots and the turning point. f(x)= x^2-2x-8 f(x)= x^2-2x-15

Question 681992: it says, "Sketch the graphs, using the function and three points: two roots and the turning point.
f(x)= x^2-2x-8
f(x)= x^2-2x-15
Found 2 solutions by ReadingBoosters, MathLover1:
Answer by ReadingBoosters(3246) (Show Source): You can put this solution on YOUR website!
f(x) =
=(x-4)(x+2)
roots/zeros/intercepts at 4 and -2
Plot (4, 0) and (-2, 0)
...
complete the square to find turning point
x^2 - 2x - 8 = 0
x^2 - 2x + 1 = 8 + 1
x^2 - 2x + 1 = 9
y = (x-1)^2 - 9
vertex/turning point at 1, -9
Plot (1,-9)
...

...
f(x) =
= (x-5)(x+3)
roots/zeros/intercepts at 5 and -3
Plot (5, 0) and (-3, 0)
...
complete the square to find the turning point
x^2 - 2x - 15 = 0
x^2 - 2x = 15
x^2 - 2x + 1 = 15 + 1
(x-1)^2 - 16 = 0
y = (x-1)^2 - 16
Plot (1,-16)
...

.....................
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Answer by MathLover1(20850) (Show Source): You can put this solution on YOUR website!
1.
...factor completely, replace with
.......group

....set

if ..=>...
if ..=>...

so, the roots are and
and points are (,) and (,)
let , solve for and find third point

so, third point is (,)
now, graph it

2.
...factor completely, replace with
.......group

....set

if ..=>...
if ..=>...

so, the roots are and
and points are (,) and (,)
let , solve for and find third point

so, third point is (,)
now, graph it

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