By using properties of deteminants.
∣∣ ∣∣0a−b−a0−cbc0∣∣ ∣∣=0
Let A=∣∣ ∣∣0a−b−a0−cbc0∣∣ ∣∣=1c∣∣ ∣∣0ac−bc−a0−cbc0∣∣ ∣∣ (using R1→cR1)
=1c∣∣ ∣∣abac0−a0−cbc0∣∣ ∣∣ (using R1→R1−bR2)
=ac∣∣ ∣∣bc0−a0−cbc0∣∣ ∣∣=0 [Since, the two row R1 and R2 are identical.]
Note: Suppose, if we multiply any row (or column) by any constant k, then we also divide that row (or column) by the same constant k and take common 1k outside the determinant.