Give an equation for the following:
If w varies directly as 2x - 1, and w = 9 when x = 2, find x when w = 15.
2006-12-26 07:42:01 · 5 answers · asked by Lawanna D 1 in Science & Mathematics ➔ Mathematics
"varies directly as" means "equals a constant multiplied by", so your information is
w = K*(2x - 1) where k is some constant (as yet unknown).
Sub in the given values w = 9, x = 2, and you have an equation which you can solve to find k.
Once you know k, sub w = 15 in the equation and solve for x.
If you can't finish it yourself I'll come back and complete in five minutes' time.
Scroll down now if you need to.
9 = k* (4 - 1) = 3k
k = 3
Hence w = 3(2x - 1)
When w = 15 we get
15 = 3(2x - 1)
5 = 2x - 1
Therefore x = 3.
2006-12-26 07:51:52 · answer #1 · answered by Hy 7 · 0⤊ 0⤋
Three.
W=Y(2x-1)
9 = Y(2*2 - 1)
Find out what Y is from the equation above and you'll find the answer
2006-12-26 15:52:43 · answer #2 · answered by Joseph T 1 · 0⤊ 0⤋
9=k(2(2)-1)
9=k(4-1)
k=3
15=3(2x-1)
Divide 3 from both sides:
5=2x-1
2x=6
x=3
2006-12-26 18:09:15 · answer #3 · answered by Anonymous · 0⤊ 0⤋
You have the answer to the 1. That should get you started.
2006-12-26 15:48:47 · answer #4 · answered by gianlino 7 · 1⤊ 0⤋
do your own homework
2006-12-26 15:49:46 · answer #5 · answered by singledad 7 · 0⤊ 1⤋