8. Упростить: а) √50 − √18 + √72; б) 0,3√32 + 1/3√18.

а) \(\sqrt{50}-\sqrt{18}+\sqrt{72}=5\sqrt{2}-3\sqrt{2}+6\sqrt{2}=8\sqrt{2}\).

б) \(0.3\sqrt{32}+\frac{1}{3}\sqrt{18}=0.3\cdot4\sqrt{2}+\frac{1}{3}\cdot3\sqrt{2}=1.2\sqrt{2}+\sqrt{2}=2.2\sqrt{2}=\frac{11\sqrt{2}}{5}\).

Ответ: а) \(8\sqrt{2}\); б) \(\frac{11\sqrt{2}}{5}\).