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

Answer:

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 :

$9 = (k \times 2) \\ k = \frac{9}{2}$

Therefore, equation is:

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