What is the value of X ?, if 7580 - X = 3440

If 12x – 15 y =9x + 5y, the value of $$ {x^{2}+{y^{2}}\over{x^{2}-y^{2}}}$$ is

What is the value of x $$ {0.081\over x}={0.09\over10}$$ ?

The value of $$ \sqrt{11.981+7\sqrt{1.2996}}$$ is closest to 

If $$ {\sqrt{1+{473\over{256}}}=1+{x\over 16}}$$ then what does x equal to ?

The square root of a positive number less than 100 lies between

If 551 ÷ 29 = 19 then 5.51 ÷ 0.0019 = ?

Simplify : $$ {(7) ^{2} ÷(7^{1\over 2})^{4}}$$