Given, the system of linear equations x+2y+z=2, αx+3y−z=α, and −αx+y+2z=−α
Now for system to be inconsistent, \Delta =0&\text{either of }{\Delta }_{1},{\Delta }_{2}\text{or}{\Delta }_{3}\neq 0
So, Δ=∣12−22311−12∣
=(6+y)−2(2α−α)+1(α+3α)
=7−2α+4α
=7+2α
Δ=0⇒α=−27
Now calculating, Δ1=∣2α−α2311−12∣
=14+2α
Where α=−27 so, Δ1=14−7=7
Δ1=0, hence system is inconsistent at α=2−7