\(\left(\frac{3x}{7}+1\right):\left(-4\right)=\frac{-1}{28}.\)

   \(\frac{3x}{7}+1=\frac{-1}{28}.\left(-4\right)\)

    \(\frac{3x}{7}=\frac{1}{7}\)

= > 3x = 1

= > x = 1 : 3

= > x = \(\frac{1}{3}\)

a) 0,45
b) 32,6
c) 1,6
d) 51,52

a, 0.45

b) 32,6

c)1.6

d) 51,52

a: =0,162:0,36=0,45

b: 912,8:28=32,6

c: =1,8

d: =51,52

Câu 1:

\(\frac{27.29-15}{27.28+12}=\frac{27.\left(28+1\right)-15}{27.28+12}=\frac{27.28+27-15}{27.28+12}=\frac{27.28+12}{27.28+12}=1\)

Câu 2:

\(\frac{45.16-17}{28+45.15}=\frac{45.\left(15+1\right)-17}{45.15+28}=\frac{45.15+45-17}{45.15+28}=\frac{45.15+28}{45.15+28}=1\)

Câu 3: Ừm... đề hơi sai nhỉ...mình sẽ chuyển mẫu số thành 24+37.12 nhé:

\(\frac{37.13-13}{24+37.12}=\frac{37.\left(12+1\right)-13}{37.12+24}=\frac{37.12+37-13}{37.12+24}=\frac{37.12+24}{37.12+24}=1\)

Câu 4: Có thể đề bạn đánh sai nên là mình chỉnh lại xíu nha:

\(\frac{423134.846267-423133}{423133.846267+423134}=\frac{\left(423133+1\right).846267-423133}{423133.846267+423134}=\frac{423133.846267+846267-423133}{423133.846267+423134}\)\(=\frac{423133.846267+423134}{423133.846267+423134}=1\)

\(703-140:\left(42+28\right)-17^6.17^9:17^{13}\)

\(=703-140:70-17^{15}:17^{13}\)

\(=703-2-17^2\)

\(=412\)