# Negative of Quotient of Real Numbers

## Theorem

$\forall x \in \R, y \in \R_{\ne 0}: \dfrac {-x} y = -\dfrac x y = \dfrac x {-y}$

## Proof

 $\displaystyle \frac {-x} y$ $=$ $\displaystyle \frac {\paren {-1} \times x} y$ Multiplication by Negative Real Number: Corollary $\displaystyle$ $=$ $\displaystyle \paren {-1} \times \frac x y$ Product of Real Number with Quotient $\displaystyle$ $=$ $\displaystyle - \frac x y$ Multiplication by Negative Real Number: Corollary $\displaystyle$ $=$ $\displaystyle \paren {-1} \times \frac x y$ Multiplication by Negative Real Number: Corollary $\displaystyle$ $=$ $\displaystyle \paren {-1} \times 1 \times \frac x y$ Real Number Axioms: $\R M3$: Identity $\displaystyle$ $=$ $\displaystyle \paren {-1} \times \frac {-1} {-1} \times \frac x y$ Real Number Divided by Itself $\displaystyle$ $=$ $\displaystyle \frac {-1 \times -1} {-1} \times \frac x y$ Product of Real Number with Quotient $\displaystyle$ $=$ $\displaystyle \frac {-\paren {-1} } {-1} \times \frac x y$ Multiplication by Negative Real Number: Corollary $\displaystyle$ $=$ $\displaystyle \frac 1 {-1} \times \frac x y$ Negative of Negative Real Number $\displaystyle$ $=$ $\displaystyle \frac {1 \times x} {\paren {-1} \times y}$ Product of Quotients of Real Numbers $\displaystyle$ $=$ $\displaystyle \frac {1 \times x} {- y}$ Multiplication by Negative Real Number: Corollary $\displaystyle$ $=$ $\displaystyle \frac x {- y}$ Real Number Axioms: $\R M3$: Identity

$\blacksquare$