If the line, `(x-3)/(2)=(y+2)/(-1)=(z+4)/(3)` lies in the plane, `lx+my-n=9`, then `l^(2)+m^(2)` is equal to

Options

A. 26
B. 18
C. 5
D. 2

Answer

D

Explanation

If the line `(x-3)/2=(y+2)/(-1)=(z+4)/3` lies in the plane `lx+my-z=9` then the point `(3,-2,-4)` lies on the plane and normal to the plane is perpendicular to the line.
`:.3l-2m+4=9` and `2l-m-3=0`
`impliesl=1,m=-1`
Hence `l^(2)+m^(2)=2`.