The correct option is A (1,2,3)
Δ=∣∣
∣∣1111−1132−4∣∣
∣∣Applying C2→C2−C1,C3→C3−C1=∣∣
∣∣1001−203−1−7∣∣
∣∣=14Δx=∣∣
∣∣6112−11−52−4∣∣
∣∣Applying R2→R2−R1,R3→R3+4R1=∣∣
∣∣611−4−201960∣∣
∣∣=14Δy=∣∣
∣∣1611213−5−4∣∣
∣∣=∣∣
∣∣1610−400−23−7∣∣
∣∣=28
and Δz=∣∣
∣∣1161−1232−5∣∣
∣∣=∣∣
∣∣1160−2−40−1−23∣∣
∣∣=42
Hence by Cramer's rule,
x=ΔxΔ=1,y=ΔyΔ=2,z=ΔzΔ=3