Equate absolute normal distances to two intersecting planes

The planes $p_1:\mathbf r\cdot(2,-2,1)=1$ and $p_2:\mathbf r\cdot(-6,3,2)=-1$ meet in line l.

(i) Find the acute angle between the planes.

(ii) Find a vector equation for l.

(iii) $A(4,3,c)$ is equidistant from the two planes. Calculate both possible values of c.