a, 73 . ( -25 ) + 25 . ( -27 )
= ( -73 ) . 25 + 25 . ( -27 )
= [ ( -73 ) + ( -27 ) ] . 25
= ( -100 ) . 25
= -2500
b, 33 . ( 17 - 5 ) - 17 . ( 33 - 5 )
= 33 . 17 - 33 . 5 - 17 . 33 + 17 . 5
= ( 33 . 17 - 17 . 33 ) + ( 17 . 5 - 33 . 5 )
= 5 . ( 17 - 33 )
= 5 . ( -16 )
= -80