Answer
$(-\infty, 14]$
Work Step by Step
Using the properties of inequality, the solution to the given expression, $
2x-7\le21
,$ is
\begin{array}{l}\require{cancel}
2x\le21+7
\\\\
2x\le28
\\\\
x\le\dfrac{28}{2}
\\\\
x\le14
.\end{array}
Hence, the solution is $
(-\infty, 14]
.$
