Question

The variables x and y vary directly. if one pair of the values is x = 3 and y = 12, write an equation that shows the relationship between x and y.

Answer 1

If they vary directly then they increase at the same amount
This can be written out with the equation
y/x=k k being the constant of the variation
In this case 12/3=4 the constant is 4
So you can say y=4x

Answer 2

The variables x and y vary directly. if one pair of the values is x = 3 and y = 12, write an equation that shows the relationship between x and y.