[tex] \sqrt{0.81} - \sqrt{0.25} + \sqrt{0.36} [/tex]
[tex] \sqrt{ \frac{81}{100} } - \sqrt{ \frac{1}{4} } + \sqrt{ \frac{9}{25} } [/tex]
[tex] \frac{9}{10} - \frac{1}{2} + \frac{3}{5} = 1[/tex]
[tex] \sqrt{( - 3) {}^{4} } \times 7 {}^{2} \times ( - 2) {}^{2} = ( - 3) {}^{2} \times 7 {}^{2} \times 2 {}^{2} = 3 {}^{2} \times 7 {}^{2} \times 2 {}^{2} = (3 \times 7 \times 2) {}^{2} = 42 {}^{2} = 1764[/tex]