Question

Determine whether y varies directly with x. If so, find the constant of variation k.
3y=-7x-18

Answer 1

I really need help with this guys...

Answer 2

If y varies directly with x; then y = kx
where k = constant

Answer 3

the graph would be linear...so I would but this given equation in standard form to make sure it is the graph of a line

Answer 4

Okay, so what points would I plot? Just plug in some numbers for "x" and "y"?

Answer 5

you don't have to plot anything to solve this problem. Standard form of a line is y= mx + b

put 3y=-7x-18 into standard form

Answer 6

isn't it already in standard form, though?

Answer 7

unless your instructions state to graph. If so, yes, pick points for x and y and graph

Answer 8

no - there is a coefficient in front of Y

Answer 9

so divide both sides by 3?

Answer 10

yes

Answer 11

So "k" would be 7/3?

Answer 12

now if you have to graph pick points for x and y and plot on graph...yes this is a line thus proving it has direct variation

Answer 13

I don't have to graph it...

Answer 14

So would it be 7/3 or -7, as "k"?

Answer 15

I guess you can say that, but -7/3 is really the slope..

Answer 16

but when you put it in the formula y=kx..then 7/3 would be "k", right?

Answer 17

-7/3

Answer 18

yeah, that's what I was thinking...but that isn't an answer choice. only 7/3 would be a choice...