a) $$\sqrt{a-b}$$ при a = -0,29, b = -0,78
$$\sqrt{-0,29 - (-0,78)} = \sqrt{-0,29 + 0,78} = \sqrt{0,49} = 0,7$$б) $$\sqrt{a-b}$$ при $$a = \frac{1}{4}$$, $$b = -\frac{4}{9}$$
$$\sqrt{\frac{1}{4} - (-\frac{4}{9})} = \sqrt{\frac{1}{4} + \frac{4}{9}} = \sqrt{\frac{9}{36} + \frac{16}{36}} = \sqrt{\frac{25}{36}} = \frac{5}{6}$$