Evaluate :

[R₂’ = (1/2)R₂]

[R₂’ = R₂ - R₃]

[R₁’ = R₁ - R₃]

[R₃’ = 2R₃]

= ( - 14){(2 × 13) - (2 × 12)} - 5{(2 × )– ( - 3) × 13} - 5{( - 3) × 12 - 2 × }

[expanding by the first row]

= - 14 × (26 - 24) - 5(81 + 39) - 5( - 36 - 81)

= - 14 × 2 - 5 × 120 - 5 × ( - 117) = - 28 - 600 + 585 = - 43