Line lies in the plane ⇒(3,−2,−4) lie in the plane ⇒3l−2m+4=9 or 3l−2m=5 .......(1) Also, l,m,−1 are dr's of line perpendicular to plane and 2 . -1,3 are dr's of line lying in the plane ⇒2l−m−3=0 or 2l−m=3 .......(2) Solving (1) and (2) we get l=1 and m=−1 ⇒l2+m2=2