Answer:
y = [tex]\frac{3}{4}[/tex] x
Step-by-step explanation:
Given that the quantities vary directly then the equation relating them is
y = kx ← k is the constant of variation
To find k use either of the 2 given points
Using (12, 9), that is x = 12 when y = 9, then
k = [tex]\frac{y}{x}[/tex] = [tex]\frac{9}{12}[/tex] = [tex]\frac{3}{4}[/tex]
y = [tex]\frac{3}{4}[/tex] x ← equation of variation
