work done when a force F=(i+2j+3k)N acting on a particle takes it from the point r1 = ( i+j+k) to the point r2= ( i - j + 2k) is

Work done is defined as the dot product of Force and displacement.
Now first we will  need to find the displacement vector which will be equal to:r₂-r₁
W=F⋅r=F⋅(r₂​−r₁​)
⇒W=(i+2j​+3k)⋅((i−j​+2k)−(i+j​+k)
⇒W=(i+2j+3k)⋅(i−j​+2k−i-j​-k)   (i.i=j.j=k.k=1)
​​​​​​⇒W=(i+2j​+3k)⋅(−2j​+k)
⇒W=−4+3=−1J