[tex]a) \sqrt{ {5}^{2} \times 3 } = \sqrt{25 \times 3} = \sqrt{75} = 5 \sqrt{3} [/tex]
[tex]b) \sqrt{49 \times {a}^{4} \times 5 } = \sqrt{ {49a}^{4} \times 5 } = \sqrt{ {245a}^{4} } = \sqrt{ {7}^{2} \times {5a}^{4} } = \sqrt{ {7}^{2} } \sqrt{ {a}^{4} } \sqrt{5} = {7a}^{2} \sqrt{5} = 7 \sqrt{5} {a}^{2} [/tex]
