Vertex form is f(x) = a(x - b)^2 + c where the vertex is (b, c) and a is some constant.
So for the first part we have f(x) = a(x + 6)^2 - 1
for root -9:- a( -9+6)^2 - 1 = 0
9a - 1 = 0 , a = 1/9
The other 3 are derived in the same way.
so required equation is f(x) = (1/9)(x + 6)^2 - 1
The have been saving for 10 weeks.
Given:
Duane = $5 every other week. meaning every 2 weeks
Mick = $2 every week
Amount Saved = $45
First, divide Duane's $5 by 2 to get his weekly contribution.
$5/2 = $2.50
let x be the number of weeks.
Duane + Mick = $45
2.50x + 2x = 45
4.50x = 45
4.50x/4.50 = 45/4.50
x = 10 weeks
to check:
2.50x + 2x = 45
2.50(10) + 2(10) = 45
25 + 20 = 45
45 = 45
12x - 18 - 4x -2
12x - 4x = 8x (yours 12x - 4x = 8)
-18 - 2 = -20 (yours -18 -1 = 17)
answer:
8x - 20
Answer:
if we take the number of quarters Barrett have to be x we know Penelope has twice that ie 2x. so in total they have 2x+x = 60, 3x = 60; so x= 60/3 = 20.
Barrett has 20 quarters.
