Bài giải
k, 98 . ( 57 + 38 ) - 38 . ( 98 + 57 )
= 98 . 57 + 38 . 98 - 98 . 38 - 38 . 57
= 98 . 57 - 38 . 57
= 57 . ( 98 - 38 )
= 57 . 60
= 3420
i, - 24 . ( 69 - 34 ) + 34 ( 50 - 24 ) - 69,76
= - 24 . 69 + 24 . 34 + 34 . 50 - 34 . 24 - 69,76
= - 24 . 69 + 34 . 50 - 69 + 0, 76
= 69 ( - 24 - 1 ) + 34 . 50 + 0,76
= 69 ( - 25 ) + 34 . 50 + 0,76
= - 25 ( 69 - 34 . 2 ) + 0,76
= - 25 + 0,76
= -24,24