=>2,6x=26

hay x=10

x   x  2,6 = 26

x = 26 : 2,6

x = 10

a) \(\left(100+67\right).67+\left(200-33\right).33\)

\(=167.67+167.33\)

\(=167.\left(67+33\right)\)

\(=167.100\)

\(=16700\)

b) \(45,651.73+45,651.20+45,651.7\)

\(=45,651.\left(73+20+7\right)\)

\(=45,651.100\)

\(=4565,1\)

c) \(14,2.30+14,2.57+14,2.13\)

\(=14,2.\left(30+57+13\right)\)

\(=14,2.100\)

\(=1420\)

_Chúc bạn học tốt_

a) (100 + 67) x 67 + (200 - 33) x 33

= 167 x 67 + 167 x 33

= 167 x (67 + 33)

= 167 x 100

= 16700

b) 45,651 x 73 + 45,651 x 20 + 45,651 x 7

= 45,651 x (73 + 20 + 7)

= 45,651 x 100

= 4565,1

c) 14,2 x 30 + 14,2 x 57 + 14,2 x 13

= 14,2 x (30 + 57 + 13)

= 14,2 x 100

= 1420

a) (100 + 67) × 67 + (200 - 33) × 33

= 167 × 67 + 167 × 33

= 167 × 100

= 16700

b) 45,651 × 73 + 45,651 × 20 + 45,651 × 7

= 45,651 × (73 + 20 + 7)

= 45,651 × 100

= 4565,1

c) 14,2 × 30 + 14,2 × 57 + 14,2 × 13

= 14,2 × (30 + 57 + 13)

= 14,2 × 100

= 1420

a)A=3+|1-x|

       Vì \(\left|1+x\right|\ge0\)

            Suy ra:\(3+\left|1+x\right|\ge3\)

Dấu = xảy ra khi 1+x=0;x=-1

                   Vậy Min A=3 khi x=-1

b)B=|4,3-x|+3,7

        Vì \(\left|4,3-x\right|\ge0\)

                Suy ra:\(\left|4,3-x\right|+3,7\ge3,7\)

Dấu = xảy ra khi 4,3-x=0;x=4,3

            Vậy Min B=3,7 khi x=4,3
 

C=2|3x+8,4|-14,2

     Vì \(2\left|3x+8,4\right|\ge0\)

           Suy ra:\(2\left|3x+8,4\right|-14,2\ge-14,2\)

                      Dấu = xảy ra khi 3x+8,4=0;x=-2,8

Vậy Min C=-14,2 khi x=-2,8

d)D=|x+1|+2|3x+8,4|-14,2

         Vì \(\left|x+1\right|\ge0\)

               \(2\left|3x+8,4\right|\ge0\)

           Suy ra:\(\left|x+1\right|+2\left|3x+8,4\right|-14,2\ge-14,2\)

                      Dấu = xảy ra khi x+1=0;x=-1

                                                3x+8,4=0;x=-2,8

Vậy Min D=-14,2 khi x=-2,8;-1

54,4 : a x 11,8 = 100,3

54,4 : a          = 100,3 : 11,8

54,4 : a         = 8,5

          a         = 54,4 : 8,5

          a        = 6,4

a: =167x100=16700

14,2% x 4 = 56,8%

a) \(2Al+6HCl\rightarrow2AlCl_3+3H_2\)

   \(Cu+HCl\rightarrow\)(không phản ứng)

    2Al + 6HCl => 2AlCl3 + 3H2

 0,3/3*2                         (6,72/22,4)

=> mAl = 0,2 *27 =5,4g; mCu = 11,8 - 5,4 = 6,4g

\(x.11,8+x.9,1=100,8\)

\(\Rightarrow x\left(11,8+9,1\right)=100,8\)

\(\Rightarrow x.20,9=100,8\)

\(\Rightarrow x=\frac{1008}{209}\)

x*11,8+x*9,1=100,8

=>x*(11,8+9,1)=100,8

=>x*20,9=100,8

=>x=100,8:20,9

=>x=\(\frac{1008}{209}\)

Vậy x=............