a/2+1.4=2+4=6
b/ko hieu
c/8:(7-12)=8:-5=-1,6
d/ko hieu

Dùng máy tính tay

a) 2+1.4 =2+4 = 6

b) bạn viết lại câu này nha!

c) 8:(7-12)= 8: (-5)= -1,6

d) bạn viết lại đề bài câu này hộ mìn nha!

Bài 1: Tìm \(x\) 

a; \(x-2\) + 7 = 1.3.(-9)

   \(x\) - 2 + 7 = 3.(-9)

   \(x\) - 2 + 7 = - 27

  \(x\)             = - 27 - 7 + 2

   \(x\)            = - 34 + 2

   \(x\)            = - 32

Vậy \(x=-32\)

Bài 1

c; - 2\(x\) + 5 = 7

     - 2\(x\)       = 7  - 5

    - 2\(x\)        = - 2

        \(x\)        = -2 : (-2)

        \(x\)        = - 1

Vậy \(x\)         = - 1

Bài 1 b; d xem lại đề bài xem chỗ trống giữa các số là dấu gì!

Ta có: \(\frac{0,8:\left(\frac{4}{5}\cdot1,25\right)}{0,64-\frac{1}{25}}+\frac{\left(1,08-\frac{2}{25}\right):\frac{4}{7}}{\left(6\frac{5}{9}-3\frac{1}{4}\right)\cdot2\frac{2}{17}}+\frac{\left(1,2\cdot0,5\right)}{\frac{4}{5}}\)

\(=\frac{\frac{4}{5}:\left(\frac{4}{5}\cdot\frac{5}{4}\right)}{\frac{16}{25}-\frac{1}{25}}+\frac{\left(\frac{27}{25}-\frac{2}{25}\right)\cdot\frac{7}{4}}{\left(\frac{59}{9}-\frac{13}{4}\right)\cdot\frac{36}{17}}+\frac{6}{5}\cdot\frac{1}{2}\cdot\frac{5}{4}\)

\(=\frac{\frac{4}{5}}{\frac{3}{5}}+\frac{\frac{7}{4}}{\frac{119}{36}\cdot\frac{36}{17}}+\frac{3}{4}\)

\(=\frac{4}{5}\cdot\frac{5}{3}+\frac{7}{4}\cdot\frac{1}{7}+\frac{3}{4}=\frac{4}{3}+\frac{1}{4}+\frac{3}{4}=\frac{7}{3}\)

cứu HELP ME''''''''''''''''''''''''''''''

a. \(10,\left(3\right)+0,\left(4\right)-8,\left(6\right)\)

\(\Leftrightarrow\dfrac{31}{3}+\dfrac{4}{9}-\dfrac{26}{3}\)

\(=\dfrac{19}{9}\)

b. \(\dfrac{0,8:\left(\dfrac{4}{5}.1,25\right)}{0,64-\dfrac{1}{25}}+\dfrac{\left(1,08-\dfrac{2}{25}\right):\dfrac{4}{7}}{\left(6\dfrac{5}{9}-3\dfrac{1}{4}\right).2\dfrac{2}{17}}+\left(1,2.0,5\right):\dfrac{4}{5}\)

\(=\dfrac{0,8}{0,6}+\dfrac{1,75}{7}+0,6:\dfrac{4}{5}\)

\(=\dfrac{0,8}{0,6}+\dfrac{1,75}{7}+\dfrac{3}{4}\)

\(=\dfrac{7}{3}\)

a, \(\dfrac{19}{9}\)

b, \(\dfrac{7}{3}\)

a.\(\dfrac{19}{9}\)

b.\(\dfrac{7}{3}\)

\(\dfrac{\dfrac{4}{5}:\left(\dfrac{4}{5}\cdot\dfrac{5}{4}\right)}{\dfrac{16}{25}-\dfrac{1}{25}}+\dfrac{\left(\dfrac{27}{25}-\dfrac{2}{25}\right):\dfrac{4}{7}}{\left(\dfrac{59}{9}-\dfrac{13}{4}\right)\cdot\dfrac{36}{17}}+\left(\dfrac{6}{5}\cdot\dfrac{1}{2}\right):\dfrac{4}{5}\)

\(=\dfrac{4}{5}:\dfrac{3}{5}+\dfrac{7}{4}:7+\dfrac{3}{5}:\dfrac{4}{5}\)

\(=\dfrac{4}{3}+\dfrac{1}{4}+\dfrac{3}{4}\)

\(=\dfrac{7}{3}\)