Find the value of given equations

$$\left({216\over1} \right) ^{-{2\over3}}÷\left({27\over1} \right) ^{-{4\over3}}=? $$

If $$ a={{\sqrt{3}+\sqrt{2}}\over {\sqrt{3}-\sqrt{2}}}$$ and $$ b={{\sqrt{3}-\sqrt{2}}\over {\sqrt{3}+\sqrt{2}}}$$, then find the value  of $$ {a^2\over b}+{b^2\over a}=?$$

The Value of $$ {\sqrt{6-\sqrt{17-2\sqrt{72}}}}$$ is closest to:

Simplify : $$ {(2x)^{2}-(2y)^{2}-(4x)^{2}}$$

Simplify the following equation.
$$ {(100)}^{1\over2}.{(0.001)}^{1\over3}-{(0.0016)}^{1\over4}.{3}^{0}+({5\over4})^{-1} $$

If $$ {y={2x-1\over x+3}}$$ find x when y=1

Evaluate: $${-(4-6)^2-3(-2)+।-6।\over 18-9÷3×5}$$

If $${a+b=10}$$ and $$ \sqrt{a\over b}-13=-\sqrt{b\over a}-11$$, then what is the value of $${3ab+4a^2+5b^2}$$?