SOLUTION: 1.Find a quadratic model for the set of values: (-2,-20), (0, -4), (4, -20) Show work please. 2. Simply the expression. -|-13| =

Algebra ->  Finance -> SOLUTION: 1.Find a quadratic model for the set of values: (-2,-20), (0, -4), (4, -20) Show work please. 2. Simply the expression. -|-13| =       Log On


   

Question 942238: 1.Find a quadratic model for the set of values: (-2,-20), (0, -4), (4, -20) Show work please.
2. Simply the expression. -|-13| =

Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
Since x=-2 and x=4 have the same y value, their average is the axis of symmetry.
x%5Bave%5D=%28-2%2B4%29%2F2=2%2F2=1
Using the vertex form,
y=a%28x-1%29%5E2%2Bb
So then,
(0,-4)
-4=a%28-1%29%5E2%2Bb
1.a%2Bb=-4
and
(-2,-20)
-20=a%28-3%29%5E2%2Bb
2.9a%2Bb=-20
Subtracting eq. 1 from eq. 2,
9a%2Bb-a-b=-20-%28-4%29
8a=-16
a=-2
So then,
-2%2Bb=-4
b=-2
.
.
.
highlight%28y=-2%28x-1%29%5E2-2%29
.
.
.
-abs%28-13%29=highlight%28-13%29