Question

If y varies inversely as x and y = 27 when x = 12 , find x when y = - 9 .

Answer 1

Answer:

x = - 36

Step-by-step explanation:

Given that y varies inversely as x then the equation relating them is

y = $\frac{k}{x}$ ← k is the constant of variation

To find k use the condition y = 27 when x = 12, then

k = yx = 27 × 12 = 324, thus

y = $\frac{324}{x}$ ← is the equation of variation

When y = - 9, then

- 9 = $\frac{324}{x}$ ( multiply both sides by x )

- 9x = 324 ( divide both sides by - 9 )

x = - 36