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

Evaluate: $$ {9।3-5।-5।-5।4।÷10\over-3(5)-2×4÷2}$$

Find the value of $$ {5^{1\over2}-[3^{1\over4}+6-4÷2]}$$

By what least number should 4320 be multiplied so as to obtain a number which is perfect cube? 

The least number, by which 1944 must be multiplied so as to make the result a perfect cube is 

In a group of 15 women, 7 have nose studs, 8 have ear rings and 3 have neither. How many of these have both nose studs and ear rings? 

Find the value of given equations

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

Given that ( 1² +2²+3²+………..+10²)=385, the value of (2²+4²+6²+……20²) is equal to