=(5,44x6-2x2,72x6)x(5,44x6-2,72)

=[5,44x(6-6)]x(5,44x6-2,72)

=0x(5,44x6-2,72)

=0

Ngoặc sau em ghi không rõ nhưng không quan trọng vì ngoặc trước có kết quả = 0

x=3,44

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

3,44

Ta có:

\(\text{4/3/4+(-0,37)+1/8+(-1,28)+(-2,5)+3/1/12}\)

\(=4:4:3-0,37+1:8-1,28-2,5+3:1:12\)

\(=\frac{1}{3}-\frac{37}{100}+\frac{1}{8}-\frac{32}{25}-\frac{5}{2}+\frac{1}{4}\)

\(=\frac{200}{600}-\frac{222}{600}+\frac{75}{600}-\frac{768}{600}-\frac{1500}{600}+\frac{150}{600}\)

\(=\frac{200-222+75-768-1500+150}{600}\)

\(=-\frac{2065}{600}\)

\(=-\frac{413}{120}\)

tính nhanh mà

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

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

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

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

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 \(x\) = - \(\dfrac{7}{2}\)

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

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

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

\(4\frac{3}{4}+\left(-0,37\right)+\frac{1}{8}+\left(-1,28\right)+\left(-2,5\right)+3\frac{1}{12}\)

\(=4,75-0,37+0,125-1,28-2,5+\frac{37}{12}\)

\(=0,725+\frac{37}{12}\)

\(=\frac{457}{120}\)

12+8/10=12,8

128/10000=0,0128

1+28/100=1,28

128/1000=0,128

12 8/10     -      12,8
128/10000          -        0,0128
1 28/100           -           1,28
128/1000               -         0,128