If a² + a + 1 = 0 then the value of a⁹ is. 

5-[4-{3-(3-3-6)}] is equal to:

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

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

If the sum and difference of two number are 20 and 8 respectively, then the difference of their squares is: 

Find the value of   $$ {(0.75)^3\over1-.75}+[0.75+(0.75)^2+1]$$

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

In a garden of 42 trees, 3/7 of them are Neem trees and the rest are Mango trees. Find the number of Mango trees.