consider the equation of the line
→r=2^i+4^j+2^k+λ(3^i+4^j+2k) ---- (i)
Let, →r=x^i+y^j+z^k
Therefore,
x^i+y^j+z^k=(2+3λ)^i+(4+4λ)^j+(2+2λ)^k
Where, x=2+3λ,y=4+4λ,z=2+2λ ---- (iii)
And
→r(^i−2^j+^k)=0 --- (ii)
Hence, (x^i+y^j+z^k)(^i−2^j+^k)=0
x−2y+z=0 --- (iv)
and the line (i) and line (ii) intersect,
Therefore, from (iii) and (iv)
+2+3λ−2(4+4λ)+2+2λ=0
2+3λ−8−8λ+2+2λ=0
−3λ=4
λ=−43
put in (iii)
x=2+3(−43),y=4+4(−43),z=2+2(−43)
Therefore, x=−2,y=−43,z=−23
Distance of point (−2,−43,−23) from (2,12,5)
=√(2+2)2+(12+43)2+(5+23)2
=√42+(403)2+(173)2
=√16+16009+2899
=√144+1600+2899
=√20339