Answer:
y = 5x and y = 45
Step-by-step explanation:
since x and y vary directly, then
y = kx ← k is the constant of variation
to find k use the given condition y = 10 when x = 2
k = [tex]\frac{y}{x}[/tex] = [tex]\frac{10}{2}[/tex] = 5
⇒ y = 5x ← is the equation that relates x and y
when x = 9 then y = 5 × 9 = 45
