40,8 : 12 - 2,03 = 1,37

6,72 : 7 + 2,15 = 3,11

  2,15 : 0,1 + 2,15 x 7 + 2,15 : 0,5 + 2,15

=2,15 x 10  + 2,15 x 7 + 2,15 x2    + 2,15 x 1

=2,15 x ( 10 + 7 + 2 + 1 )

= 2,15 x 20

=  43 

OK CHÚC BẠN HỌC TỐT !!!  

=2,15 x 10 + 2,15 x 7 + 2,15 x 2 + 2,15 x 1

=2,15 x (10+7+2+1)

=2,15 x 20 = 43

2,15 : 0,1 + 2,15 x 7 + 2,15 : 0,5  + 2,15

= 2,15 : 0,1 + 2,15 : 0,5 + 2,15 x 7 + 2,15 x 1

= 2,15 : (0,1 + 0,5) + 2,15 x (7 + 1)

= 2,15 : 0,6 + 2,15 x 6

= 2,15 x \(\frac{3}{5}\) + 2,5 x 6

= 2,15 x (\(\frac{3}{5}\) + 6)

= 2,15 x \(\frac{33}{5}\)

= \(\frac{1419}{100}\)= 14,19

\(2,15\times123,06-2,15\times23,06+17,8\)

\(=2,15\times\left(123,06-23,06\right)+17,8\)

\(=2,15\times100+17,8\)

\(=215+17,8\)

\(=232,8\)

\(2,15\times123,06-2,15\times23,06+17,8\)

\(=2,15\times\left(123,06-23,06\right)+17,8\)

\(=2,15\times100+17,8\)

\(=215+17,8\)

\(=232,8\)

`2,15 xx 132,06 -2,15 xx 23,06 + 17,85`

`=2,15 xx(132,06 -23,06 )+ 17,85`

`=2,15 xx109+ 17,85`

`=234,35+ 17,85`

`=252,2`

=2,15(132,06-23,06)+17,85

=2,15*109+17,85

=252,2

\(2,15\times132,06-2,15\times23,06+17,85\)

\(=2,15\times\left(132,06-23,06\right)+17,85\)

\(=2,15\times109+17,85\)

\(=234,35+17,85\)

\(=252,2\)

  2,15 x 23,06 + 2,15 x 76,94 + 17,85

=2,15 x ( 23,06 + 76,94 ) + 17,85

=2,15 x 100 + 17,85

=215 + 17,85

=232,85

2.15 * 23.06 + 2.15 * 76.94 + 17.85

2.15 *[23.06+76.94+17.85]

2.15 *117.85

253.3775

2,15 x 23,06 + 2,15 x 76,94 + 17,85 

= 2,15 x ( 23,06 + 76,94 ) + 17,85 

= 2,15 x 100 + 17,85

= 215 + 17,85

= 232,85

4,3 * 6,5 + 2,15 * 37 + 2,15 * 27 - 2,15

= 2,15 * 13 + 2,15 * 37 + 2,15 * 27 - 2,15

= 2,15 * ( 13 + 37 + 27 - 1 )

= 2,15 * 76

= sai đề

Mình chưa tìm ra cách giải???

Ta có: ( -5/4 . x + 2,15 ) . [ 17/7 - ( -1/2 . x ) ] = 0

<=> ( -5/4 . x + 2,15 )  = 0

       [ 17/7 - ( -1/2 . x ) ] = 0

<=> -5/4.x = -2,15

        -1/2.x = 17/7

<=> x = -2,15 : (-5/4)

       x = 17/7 : (-1/2)

<=> x = 43/25

       x = -34/7

=0 nha bn

Ta có:( -5/4 . x + 2,15 ) . [ 17/7 - ( -1/2 . x ) ] = 0

=> (  -5/4 . x + 2,15)=0 và [ 17/7 - ( -1/2 . x ) ] = 0

=> -5/4.x=-2,25

x=43/25

 [ 17/7 - ( -1/2 . x ) ] = 0

=> -1/2.x=17/7

x=-34/7

Cách 1: (2,15 + 3,85) x 1,2
= 6 x 1,2
= 7,2
Cách 2: (2,15 + 3,85) x 1,2
= 2,15 x 1,2 + 3,85 x 1,2
= 2,58 + 4,62
= 7,2