Question

The following table shows a proportional relationship between x and y.

x y
2 9
5 22.5
8 36
Write an equation to describe the relationship between x and y.

Answer 1

Assume x is directly proportional to y :

`y \: \alpha \: x \\ y = kx`

when y is 9, x is 2:

substitute to find value of k :

`9 = (k * 2) \\ k = (9)/(2)`

Therefore, equation is:

`{ \boxed{ \boxed{2y = 9 x}}}`