7) √81/√361 + √(1/4);

\(\sqrt{81}=9\), \(\sqrt{361}=19\), \(\sqrt{\frac14}=\frac12\).

\(\frac{9}{19}+\frac12=\frac{18}{38}+\frac{19}{38}=\frac{37}{38}\).

Ответ: \(\frac{37}{38}\).