Question

How do I solve this step by step?

Answer 1

`\bf \cfrac{4}{5}-k=\cfrac{21}{20}\impliedby \begin{array}{llll} \textit{let's multiply both sides by }\stackrel{LCD}{20}\\ \textit{to do away with the denominators} \end{array} \\\\\\ 20\left( \cfrac{4}{5}-k \right)=20\left( \cfrac{21}{20} \right)\implies 16-20k=21 \\\\\\ 16-21=20k\implies -5=20k\implies \cfrac{-5}{20}=k\implies -\cfrac{1}{4}=k`