Question

Assume that y varies directly with x. If y = 18 when x = -3, find x when y = 6.

Answer 1

Ok, so:

Here we have that both variables are directly proportional. Then, we propose a rule of three, like this:

18 ------ -3

6 ------ x

So, if we want to find x, we multiply the extremes and divide by the other side:

x = (6*(-3))/18

And this is equal to: x= -1.