Answer
$(-9,0,14)$
Work Step by Step
Since, we have $\overrightarrow{AB}=-7i+3j+8k$,$A=(-2,-3,6)$ and suppose $B=(p,q,r)$
$\overrightarrow{AB}=(p+2)i+(q+3)j+(r-6)k=-7i+3j+8k$
Now, $p+2=-7, q+3=3, r-6=8$
Thus, $p=-9,q=0,r=14$
Hence, $B=(-9,0,14)$
