Question

y is inversely proportional to x.when y=7 x=9 a) work out an equation connecting y and x b) work out the value of y when x=21

Answer 1

a) y = k/x

7 = k/9

b) y = 3

Explanation:

From the question, we are told that:

y is inversely proportional to x.

Mathematically:

y ∝ 1/x

y = k × 1/x

y = k/x

k = Constant of Proportionality

a) work out an equation connecting y and x

To find this Equation,

y = k/x

when y=7 x=9

Hence:

7 = k/9

b) work out the value of y when x=21

We find the value of k first

7 = k/9

k = 7 × 9

k = 63

Hence, the value of y when x=21

y = k/x

k = 63, x = 21

y = 63/21

y = 3