Question

a) Tính \(\sqrt{18}:\sqrt{50}\);

b) Rút gọn \(\sqrt{16ab^2}:\sqrt{4a}\) (với a > 0, b < 0)

Answer 1

a) \(\sqrt {18} :\sqrt {50}  = \sqrt {\frac{{18}}{{50}}}  = \sqrt {\frac{9}{{25}}}  = \sqrt {{{\left( {\frac{3}{5}} \right)}^2}}  = \frac{3}{5}\)

b) \(\sqrt {16a{b^2}} :\sqrt {4a}  = \sqrt {\frac{{16a{b^2}}}{{4a}}}  \)\(= \sqrt {4{b^2}}  = \sqrt {{{\left( {2b} \right)}^2}}  = \left| {2b} \right| =  - 2b.\)