find a unit vector in the direction of the resultant of the vectors i-j+3k, 2i+j-2k and i+2j-2k

The vector given are :
i - j + 3k, 
2i + j - 2k
and i + 2j - 2k

There resultant is simply add all there vectors .
Hence the resultant vector is  4i  + 2j - k

And the magnitude of resultant vector is √[(4² + 2² + (-1)²]  = √21

Hence the unit vector is  (4i  + 2j - k) / √21