Question

Tinh nhanh ( neu co ) :

255 - 21 . 5 . ( 198 : 11 - 8 )

Tim x :

720 : [ 41 - ( 2 . x . 5 ) ] = 2 ³ . 5

Mong cac ban giup, minh can gap 

Answer 1

255 - 21 . 5 . ( 198 : 11 - 8 )

= 255 - 105 . ( 18 - 8 )

= 255 - 105 . 10

= 255 - 1050

= -795

Answer 2

720 : [ 41 - ( 2 . x . 5 ) ] = 2³ . 5

720 : [ 41 - ( 10 . x ) ] = 40

41 - ( 10 . x ) = 720 : 40

41 - ( 10 . x ) = 18

10 . x = 41 - 18

10 . x = 23

x = 23/10

Answer 3

Tinh nhanh ( neu co ) :

255 - 21 . 5 . ( 198 : 11 - 8 )

= 255 - 21 . 5 . ( 18 - 8 )

=255 - 21 . 5 . 10

=255 - 1050

= -795