Mathematics - Determinant Question with Solution | TestHub

If the system of equations

$P_1: kx+y+2z=1$

$P_2: 3x-y-2z=2$

$P_3: -2x-2y-4z=3$

Which are equivalent to equations of planes.

We observe $5P_2-P_1=3P_3$

So, $15-K=-6$

$\Rightarrow K=21$