If two variables are directly proportional, it means that an increase in the value of one variable would cause a corresponding increase in the other variable.
Given that y varies directly with x, if we introduce a constant of proportionality, k, the expression becomes
y = kx
If y = 8 when x = 3, then
8 = 3k
k = 3/8
Therefore, the direct variation equation that relates x and y is