2) Найдите значение выражения √(a + c) при a = −0,27, c = 0,63; a = 3/4, c = 1/18.

1. При \(a=-0.27\), \(c=0.63\):
   \(\sqrt{a+c}=\sqrt{-0.27+0.63}=\sqrt{0.36}=0.6\).
2. При \(a=\frac{3}{4}\), \(c=\frac{1}{18}\):
   \(\sqrt{a+c}=\sqrt{\frac{3}{4}+\frac{1}{18}}=\sqrt{\frac{27}{36}+\frac{2}{36}}=\sqrt{\frac{29}{36}}=\frac{\sqrt{29}}{6}\).

Ответ: 0,6; \(\frac{\sqrt{29}}{6}\).