Question 934263: 1)Does y vary directly, inversely or neither with x? If so, write the equation for the variation. (It's a chart but I'll type them for x and y)
x - -2, 3, 8
y- -2.8, 4.2, 11.2
2)Does y vary directly, inversely or neither with x? If so, write the equation for the variation.
x- 4, 5, 11
y- 3, 4.5, 13.5.
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! if they vary directly, then k = y/x
if they very inversely, then k = y*x
this is because the equation for direct variation is y = k*x
solve for k and you get k = y/x
the equation for inverse variation is y = k/x
solve for k and you get k = y*x
k has to be the same for all of the pairs, not just some of them.
your first series is:
x = -2, 3, 8
y = -2.8, 4.2, 11.2
we'll look for direct variation first.
-2.8 / -2 = 1.4
4.2 / 3 = 1.4
11.2 / 8 = 1.4
it's a direct variation equation.
your second series is:
x = 4, 5, 11
y = 3, 4.5, 13.5.
we'll look for direct variation first.
3/4 = .75
4.5 / 5 = .9
it's not a direct variation.
let's look for inverse.
3 * 4 = 12
4.5 * 5 = 22.5
it's not an inverse variation.
this one is neither.
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