Using properties of determinants prove that:
[R1’ = R1 + R2 + R3]
[R1’ = R1/(5x + )]
[R2’ = R2 - R3]
[R2’ = R2/(x - )]
= (5x + )(x - )[ - (x + ) - 2x + 2x - 0 + 0 - ( - 2x)] [expansion by first row]
= (5x + )(x - )( - x - + 2x) = (5x + )(x - )2