Given,
1x+2=−2y=2z−5
1x−4=2y−1=0z+3
Now we know that,
Shortest distance between two skew lines is given by,
SD=∣∣n1×n2∣(a2−a1)(n1×n2)∣
Now finding, n1×n2=∣i^11j^−22k^20∣
⇒n1×n2=−4i^+2j^+4k^
And a2−a1=(4i^+j^−3k^−(−2i^+0j^+5k^))=6i^+j^−8k^
Now putting the value in formula we get,
SD=∣16+16+4(6i^+j^−8k^)(−4i^+2j^+4k^)∣
⇒SD=∣6−24+2−32∣=654=9