Find the Constant of Variation -16=4xy

$- 16 = 4 x y$

Rewrite the equation as $4 x y = - 16$ .

$4 x y = - 16$

Divide each term in $4 x y = - 16$ by $4 x$ and simplify.

Divide each term in $4 x y = - 16$ by $4 x$ .

$\frac{4 x y}{4 x} = \frac{- 16}{4 x}$

Simplify the left side.

Cancel the common factor of $4$ .

Cancel the common factor.

$\frac{4 x y}{4 x} = \frac{- 16}{4 x}$

Rewrite the expression.

$\frac{x y}{x} = \frac{- 16}{4 x}$

Cancel the common factor of $x$ .

Cancel the common factor.

$\frac{x y}{x} = \frac{- 16}{4 x}$

Divide $y$ by $1$ .

$y = \frac{- 16}{4 x}$

Simplify the right side.

Cancel the common factor of $- 16$ and $4$ .

Factor $4$ out of $- 16$ .

$y = \frac{4 \cdot - 4}{4 x}$

Cancel the common factors.

Factor $4$ out of $4 x$ .

$y = \frac{4 \cdot - 4}{4 (x)}$

Cancel the common factor.

$y = \frac{4 \cdot - 4}{4 x}$

Rewrite the expression.

$y = \frac{- 4}{x}$

Move the negative in front of the fraction.

$y = - \frac{4}{x}$

The given equation $y = - \frac{4}{x}$ can not be written as $y = k x$ , so $y$ doesn\'t vary directly with $x$ .

$y$ doesn\'t vary directly with $x$