Question

can someone helps??? please! Y varies inversely with x. If y = 6 when x = 5, find x when y = 7

Answer 1

if y varies inversely with x, that means that \(y = \frac{k}{x}\) where \(k\) is a constant. Use y = 6 and x = 5 to find \(k\), then use \(k\) to find the value of x when y = 7.

Answer 2

Right, as whpalmer has shown

\[y = \frac{ k }{ x }\]

putting your values to solve for k

\[6 = \frac{ k }{ 5 }\]

how do we solve for 'k'? we multiply both sides by 5

k = 30

now you go back to the original equation

\[y = \frac{ k }{ x }\]

you have a 'y' value and now a 'k' value...so plug those in and solve for 'x'

\[7 = \frac{ 30 }{ x }\]

x = ...?