Question

tinh nhanh 

65 . (-19) + 19 .( -24) 

71 . 64 - 32 .( -7) + 32 . 11

Answer 1

65.(-19)+19.(-24)
=(-65).19+19.(-24)
=19.(-65+(-24))
=19.(-41)
=-779
 

Answer 2

Tính nhanh : 

65 . (-19) + 19 . (-24)

= (-65) . 19 + 19 . (-24)

= 19 . [ (-65) + (-24) ]

= 19 . (-89)

= -1691 

71 . 64 - 32 . (-7) + 32 . 11 

= 71 . 2 . 32 - 32 . (-7) + 32 .11

= 142 . 32 - 32 . (-7) + 32 . 11

= 32 . [ 142 - ( -7)  + 11 ]

= 32 . ( 142 + 7 + 11 )

= 32 . ( 149 + 11 )

= 32 . 160

= 5120

Answer 3

a, 65 . ( -19 ) + 19 . ( -24 )

= ( -65 ) . 19 + 19 . ( -24 )

= 19 [ ( -65 ) + ( - 24 ) ]

= 19 . ( -89 )

= -1691

b, 71 . 64 - 32 . ( -7 ) + 32 . 11 

= 71 . 64 - 32 [ ( -7 ) + 11 ] 

= 71 . 64 - 32 . 4

= 4544 - 128

= 4416