Question

1: Tính thuận tiện

a) 2x31x12+4x6x42+8x27x3

b) (68x8686 - 6868x86) x(1+2+3+...+2016)

Mn giúp mk nha 

 

Answer 1

a)Chịu

b)(68x8686 - 6868x86) xA = {[68x(86x101)] - [(68x101)x86]} xA =[(68x86x101) - (68x101x86)] xA = 0 xA = 0

Answer 2

a) 2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3

= ( 2 x 12 ) x 31 + 24 x 42 + ( 8 x 3 ) x 27

= 24 x 31 + 24 x 42 + 24 x 27

= 24 x ( 31 + 42 + 27 )

= 24 x 100

= 2400

b) ( 68 x 8686 - 6868 x 86) x ( 1 + 2 + 3 + ... + 2016 )

= ( 68 x 86 x 101 - 68 x 101 x 86 ) x ( 1 + 2 + 3 + ... + 2016 )

= 0 x ( 1 + 2 + 3 + ... +2016 )

= 0

Answer 3

câu b thoy ạ 

Answer 4

a)2x31x12+4x6x42+8x27x3 = [(2x12)x31]+[(4x6)x42]+[(8x3)x27] = 24x31 + 24x42 +24x27 = 24x(31+42+27) = 24x100 = 2400. Mình bổ sung vào nhé :)