The value of `[-1.9]` is

The value of [5.7 div 1.9 " of " 0.4] div 1.5 is :

The value of [1/(sqrt9-sqrt8)]-[1/(sqrt8-sqrt7)]+[1/(sqrt7-sqrt6)]-[1/(sqrt6-sqrt5)]+[1/(sqrt5-sqrt4)] is A)6 B)5 C)-7 D)-6

If a^(2)+a+1=0 , then the value of a^(9) is

Find the value of: ( -1/9 )^(-1/2 )