(3 − 2) × (2 − 1) (3 − 2) × (2 = 3 × (2 − 1) + (−2) × (2 − 1) − 1) 2 = − + ( + ) 2 = − + × 3 −2 = − + ( + ) 2 2 2 2 = − + −1 + = + + ( + ) = ( + ) + [ × ( + ) = ( × ) + ( × )] [( + ) × = ( × ) + ( × )]