Question

Sixteen was added to the product of a number and 3. The result was 5 less than the product of the same number and -4. What was the number?

Answer 1

$\begin{gathered} 16+3x=y\text{ (1)} \\ y-5=-4x\text{ (2)} \\ \text{rewriting (1) and (2)} \\ 3x-y=-16 \\ -4x-y=-5 \\ \text{the n}umber\text{ is }\frac{-11}{7} \end{gathered}$