Question

The product of two numbers is $\frac{-81}{2}$. If one of the numbers is $9$, find the other.

Answer 1

Let the number be $x$
Given that
$9\times x=\frac{-81}{2}$
$\Rightarrow \frac{9\times x}{9}=\frac{\frac{-81}{2}}{9}$
$\Rightarrow x=\frac{-81}{2}÷9$
$\Rightarrow x=\frac{-81}{2}\times \frac{1}{9}$
$\Rightarrow x=\frac{-81}{2\times 9}$
$\Rightarrow x=\frac{-9}{2}$
Hence, the second number is $\frac{-9}{2}$.