a) ( - 78 ) . ( 1 + 187 ) + 187 . 78
= ( - 78 ) + ( - 78 ) . 187 + 187 . 78
= ( - 78 ) + 187 . [ ( - 78 ) + 78 ]
= ( - 78 ) + 187 . 0
= ( - 78 ) + 0
= ( - 78 )
b) ( - 39 ) . 15 - 36 . 39 - 49 . ( - 39 )
= ( - 39 ) . 15 + 36 . ( - 39 ) - 49 . ( - 39 )
= ( - 39 ) . ( 15 + 36 - 49 )
= ( - 39 ) . 2
= - 78
a) (-78).(1+187) + 187.78 = -78 - 78.187 +187.78 = -78
b) (-39).15 - 36.39 - 49.(-39)
= -39.15 - 36.39 + 49.39
=39.(-15-36+49)
= 39.(-2)
= - 78
Tích mk nha !!!!~~
a) ( -78 ) . ( 1+187 ) + 187 . 78
= 78 . -(1+187) +187 . 78
=78 . -188 + 187 . 78
= 78 . ( -188 + 187 )
=78 . -1 = -78
b) ( -39 ) .15 -36 . 39 -49.(-39)
=(-39).15+36.(-39) - 49 .(-39)
=-39. ( 15+36-49)
=-39 . 2
=-78
học tốt ~~~