For each function, y varies directly with x. Find each constant variation. Then find the value of y when x= -0.3.

1. y=2 when x= -1/2

2. y= 2/3 when x= 0.2

3. y=7 when x= 2

4. y=4 when x= -3

Question

For each function, y varies directly with x. Find each constant variation. Then find the value of y when x= -0.3.

1. y=2 when x= -1/2

2. y= 2/3 when x= 0.2

3. y=7 when x= 2

4. y=4 when x= -3

luigi0210 · Answer

Direct variation equation for this is:
y=kx

anonymous · Answer

set the direct variation equation to k. This is how you will solve fro k since you are given y and x

anonymous · Answer

for*

luigi0210 · Answer

So example one, start!

luigi0210 · Answer

So we have the equation: y=kx
We are also given x=-.3 and y=2
So plug this in and solve for k:
2=-.3k

awkwardpanda · Answer

So... ahem. I divide by 2?

luigi0210 · Answer

We're solving for k. So divide by -.3

anonymous · Answer

@Luigi0210 don't you have to solve for constants first then find the value of y when x = -.3 for each function?

anonymous · Answer

So i'm asking isn't the 2nd part of the question asking for a new y value?

luigi0210 · Answer

Yup, that's what I'm doing. Then after that we plug that value of k back in with the x value provided to get the new y.

awkwardpanda · Answer

$$2/ -.3k =-.3k/-.3k$$

awkwardpanda · Answer

$$-6.66=k$$

awkwardpanda · Answer

right?

luigi0210 · Answer

Yea, so now do y=k(-1/2)
Plug in the k you got.

luigi0210 · Answer

Try leaving answers in fraction form, unless told other wise.