Is it possible to add two vectors of unequal magnitude and get a resultant of zero?Please explain also.

Not possible

no it is not possible as .. if the magnitude is diffrent then they cannot cancel....

soo... if the resultant has to b zero then the vectors should have same ma n diff direction

 it is not possible .for two vectors to give zero resultant their components along the x and y axis must cancel each other which is not possible for this  case. 

PT:
|x| is not = |y|
x+y=0

therefore, x=-y
therefore, we get |-y| and |y|, but they are equal, therefore |x|=|y|,
For a simple example, Take a block of unit mass kept on a table. You and your friend are applying equal and opposite forces on it, it wont move. But call your dad and ask him to replace your friend, the block will move towards you.