Given,
a=i^+2j^+3k^, b=i^+j^−k^, a⋅c=11, b⋅(a×c)=27 and b⋅c=−3∣b∣
Now finding, (b×a) we get,
(b×a)=∣i^11j^12k^−13∣=5i^−4j^+k^
Let c=c1i^+c2j^+c3k^
Now solving, a⋅c=11 we get,
c1+2c2+3c3=11.......(1)
Now solving, b⋅c=−3∣b∣ we get,
c1+c2−c3=−33
c1+c2−c3=−3..........(2)
Now solving (b×a)⋅c=27 we get,
5c1−4c2+c3=27...........(3)
Now on solving equation (1),(2)&(3) we get,
c=3i^−2j^+4k^
Hence, ∣a×c∣2=∣i^13j^2−2k^3+4∣2=∣14i^+5j^−8k^∣2
⇒∣a×c∣2=142+52+82=285