a)
\(\eqalign{& \sqrt 2 + \sqrt 8 + \sqrt {50} = \sqrt 2 + \sqrt {\left( {{2^2} \times 2} \right)} + \sqrt {\left( {{5^2} \times 2} \right)} \cr & = \sqrt 2 + 2\sqrt 2 + 5\sqrt 2 = 8\sqrt 2 \cr} \)
b)
\(\eqalign{& 4\sqrt 3 + \sqrt {27} - \sqrt {45} + \sqrt 5 = 4\sqrt 3 + \sqrt {\left( {{3^2} \times 3} \right)} - \sqrt {\left( {{3^2} \times 5} \right)} + \sqrt 5 \cr & = 4\sqrt 3 + 3\sqrt 3 - 3\sqrt 5 + \sqrt 5 = 7\sqrt 3 - 2\sqrt 5 \cr} \)
