If $\frac{a^{2}+b^{2}}{c^{2}+d^{2}}=\frac{a b}{c d},$ then find the value of $\frac{a+b}{a-b}$ in terms of $c$ and $d$ only.

$67.99 \%$ of $1401 - 13.99 \%$ of $1299 = ?$

If $M = \left(\frac{3}{7}\right) \div \left(\frac{6}{5}\right) \times \left(\frac{2}{3}\right) + \left(\frac{1}{5}\right) \times \left(\frac{3}{2}\right)$ and $N = \left(\frac{2}{5}\right) \times \left(\frac{5}{6}\right) \div \left(\frac{1}{3}\right) + \left(\frac{3}{5}\right) \times \left(\frac{2}{3}\right) \div \left(\frac{3}{5}\right)$,then what is the value of $\frac{M}{N}$?

$\frac{(0.1667)(0.8333)(0.3333)}{(0.2222)(0.6667)(0.1250)}$ is approximately equal to

If $a=25, b=15, c=-10$; then the value of $\frac{a^{3}+b^{3}+c^{3}-3abc}{(a-b)^{2}+(b-c)^{2}+(c-a)^{2}}$ is

If $a$ and $b$ are rational numbers and $(a-1) \sqrt{2} + 3 = b \sqrt{2} + a$,then the value of $(a+b)$ is