Simple...
you have: \(\sqrt{5k} +2+8=11\)
-->>Isolate the variable...
\(\sqrt{5k} +2+8=11\)
\(\sqrt{5k} +10=11\)
\(\sqrt{5k} +10=11\)
-10 -10
\(\sqrt{5k} =1\)
What is the opposite of square root? \((x)^{2}\)
\(\sqrt{5k} ^{2} = 1^{2}\)
5k=1
Now simply divide-->>
k=\(\frac{1}{5}\)
Thus, your answer.