Let the given point be $A(1,-1,2) B(3,4,-2)$ and $ C(0,3,2)$ and $D(3,5,6)$

The direction ratios of the line joinig $A$ and $B$ is $(3,1),(4-(-1)),(-2-2)$

On simplifying we get,

$(2,5,-4)$

The direction ratios of the line joinig $C$ and $D$ is $(3-0),(5-3),(6-2)$

On simplifying we get,

$(3,2,4)$

For the lines $AB$ and $CD$ to be perpendicular

$a_1a_2+b_1b_2+c_1c_2=0$

On substituting for $a_1,b_1,c_1$ and $a_2,b_2,c_2$ we get,

$=(2 \times 3)+(5 \times 2)+(-4 \times 4)$

$=6+10-16$

$=0$

Hence $AB \perp CD$