1,28:0,125+1,28.0,25+1,8.1,75

=1,28.\(\frac{1}{8}\)+1,28.\(\frac{1}{4}\)+1,8.\(\frac{7}{10}\)

=1,28\(\left(\frac{1}{8}+\frac{1}{4}\right)\)+\(\frac{9}{5}\).\(\frac{7}{10}\)

=1,28\(\left(\frac{1}{8}+\frac{2}{8}\right)\)+\(\frac{63}{50}\)

=\(\frac{32}{25}\cdot\frac{3}{8}+\frac{63}{50}\)

\(=\frac{12}{25}\)

Các bạn viết hẳn ra ạ

a) 1,28:0,125+1,28×0,25+1,28×1,75

=1,28x(8+0,25+1,75)

=1,28x10=12,8

b) bạn nên viết rõ ra

\(1,28\cdot5+1,28:0,25+1,28\)

\(=1,28\cdot5+1,28\cdot4+1,28\)

\(=1,28\left(5+4+1\right)\)

\(=1,25\cdot10=12,5\)

X=16:(1,28:0,5)=6,25

\(16:x=1,28:0,5\\ 16:x=2,56\\ x=16:2,56\\ x=6,25\)

16:x=1,28:0,5

16:x=2,56

     x=16:2,56

     x=6,25

X + 1,2 = 4,58 + 1,28

X + 1,2 = 5,86

X          = 5,86 - 1,2 

X          = 4,66

X - 3,2 = 5 + 4,2

X - 3,2 = 9,2

X         = 9,2 - 3,2

X         = 6

18 nhân X = 0,18

              X = 0,18 : 18

              X = 0,01

x=3,44

\(x\times12=40+1,28\\ \Rightarrow x\times12=41,28\\ \Rightarrow x=41,28:12\\ \Rightarrow x=3,44\)

3,44

7:2 = 7/2

1,25 x2 = 2,5

1,28 x 4 = 5,12

59:2=59,2

\(7:2=3,5\)

\(1,25\times2=2,5\)

\(1,28\times4=5,12\)

\(59:2=29,5\)

\(7\div2=3\) dư \(1\),  \(7\div2=\dfrac{7}{2}\) hoặc \(7\div2=3,5\)

\(1,25\times2=2,5\)

\(1,28\times4=5,12\)

\(59\div2=29\) dư \(1,59\div2=\dfrac{59}{2}\) hoặc \(59\div2=29,5\)

12 : (x * 3) = 1,28 + 2,72

12 : (x * 3) = 4

x * 3 = 12 : 4

x * 3 = 3

x = 3 : 3

x = 1

`->` x = 1.

Bài 1:

0,5\(x\) - \(\dfrac{2}{3}\)\(x\) = \(\dfrac{7}{12}\)  

\(\dfrac{1}{2}\)\(x\) - \(\dfrac{2}{3}x\)  = \(\dfrac{7}{12}\)

(\(\dfrac{1}{2}-\dfrac{2}{3}\))\(x\) = \(\dfrac{7}{12}\)

- \(\dfrac{1}{6}\)\(x\)         = \(\dfrac{7}{12}\)

     \(x\)         = \(\dfrac{7}{12}\) : (- \(\dfrac{1}{6}\))

     \(x\)        = - \(\dfrac{7}{2}\)

Vậy \(x\) = - \(\dfrac{7}{2}\)