A

A

A

\(9:27^x=\dfrac{1}{18}\)

\(\Rightarrow9:\left(3^3\right)^x=\dfrac{1}{18}\)

\(\Rightarrow3^{3x}=9:\dfrac{1}{18}\)

\(\Rightarrow3^{3x}=162\)

Xem lại đề 

\(\frac{1.5.18+2.10.36+3.15.54}{1.3.9+2.6.18+3.9.27}=\frac{1.5.18.\left(1+2.2.2+3.3.3\right)}{1.3.9.\left(1+2.2.2+3.3.3\right)}\)

\(=\frac{1.5.18}{1.3.9}=\frac{10}{3}\)

9 + 18 + 27 + 36 + 45 + 54 + 63 + 72 + 90 = 414

kết quả là :

   414 

      đs...

1 x 9 = 9

2 x 9 = 18

3 x 9 = 27

4 x 9 = 36

5 x 9 = 45

6 x 9 = 54

7 x 9 = 63 

8 x 9 =72

9 x 9 = 81

10 x 9 = 90

Câu hỏi là : 9 + 18 + 27 + 36 + 45 + 54 + 63 + 72 + 81 +90 =414

\(\frac{5}{9}-x\times\frac{1}{27}=\frac{6}{18}\)

\(x\times\frac{1}{27}=\frac{5}{9}-\frac{1}{3}\)

\(x\times\frac{1}{27}=\frac{5}{9}-\frac{3}{9}\)

\(x\times\frac{1}{27}=\frac{2}{9}\)

\(x=\frac{2}{9}\div\frac{1}{27}\)

\(x=2\)

Chúc bạn học tốt

bạn sửa lại nhé ở câu cuối x = 6

\(\frac{5}{9}-x\times\frac{1}{27}=\frac{6}{18}\)

\(x\times\frac{1}{27}=\frac{5}{9}-\frac{1}{3}\)

\(x\times\frac{1}{27}=\frac{5}{9}-\frac{3}{9}\)

\(x\times\frac{1}{27}=\frac{2}{9}\)

\(x=\frac{2}{9}\div\frac{1}{27}\)

\(x=6\)

Học tốt

       \(\frac{5}{9}-x\times\frac{1}{27}=\frac{6}{18}\)

                   \(x\times\frac{1}{27}=\frac{5}{9}-\frac{6}{18}\)

                   \(x\times\frac{1}{27}=\frac{2}{9}\)

                   \(x\)         \(=\frac{2}{9}\div\frac{1}{27}\)

                   \(x\)         \(=6\)

Bài 1:

a: \(=\dfrac{21}{7}\cdot\dfrac{15}{45}\cdot\dfrac{9}{18}=3\cdot\dfrac{1}{3}\cdot\dfrac{1}{2}=\dfrac{1}{2}\)

b: \(=\dfrac{11}{33}\cdot\dfrac{24}{8\cdot12}\cdot\dfrac{27}{9}=\dfrac{24}{96}=\dfrac{1}{4}\)