# How do you write inverse variation equation given x = 3, y=7?

Sep 2, 2017

$y = \frac{21}{x}$

#### Explanation:

$\text{the initial statement is } y \propto \frac{1}{x}$

$\text{to convert to an equation multiply by k the constant of}$
$\text{variation}$

$\Rightarrow y = k \times \frac{1}{x} = \frac{k}{x}$

$\text{to find k use the given condition}$

$x = 3 , y = 7$

$y = \frac{k}{x} \Rightarrow k = x \times y = 3 \times 7 = 21$

$\text{equation is } \textcolor{red}{\overline{\underline{| \textcolor{w h i t e}{\frac{2}{2}} \textcolor{b l a c k}{y = \frac{21}{x}} \textcolor{w h i t e}{\frac{2}{2}} |}}}$