Let a=xi^+yj^+zk^
So,∣i^x1j^y1k^zλ∣=i^(λy−z)+j^(z−λx)+k^(x−y)
On comparing with 13i^−j^−4k^ we get,
⇒λy−z=13,z−λx=−1,x−y=−4
and x+y+λz=−21
⇒ Clearly, λ=3,x=−2,y=2 and z=−7
So, b−a=3i^−j^+10k^ and b+a=−i^+3j^−4k^
⇒(b−a)⋅(k^−j^)+(b+a)⋅(i^−k^)=11+3
=14