a) \(\frac{27.45+55.27}{2+4+6+8+...+16+18}=\frac{27.\left(45+55\right)}{\left(2+18\right)+\left(16+4\right)+\left(14+6\right)+\left(12+8\right)}\)

\(=\frac{27.100}{20+20+20+20}=\frac{2700}{20.4}=\frac{2700}{80}=\frac{135}{4}\)

b) Lười

Làm giống câu a nhé

xin lỗi! mik ko rảnh

  2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3 

= 24  x  31  +  24  x  42  +  24  x  27

= 24 x ( 31 + 42 + 27 )

= 24 x 100

= 2400

  2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3

= 24 x 31 + 24 x 42 + 24 x 27

= 24 x ( 31 + 42 + 27

= 24 x 100

= 2400

2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3 

= 2x 31 x 4 x 3 + 4 x 3 x 2 x 42 + 4 x 2 x 27 x 3

= 4 x 3 x 2 x ( 31 + 42 + 27 )

= 24 x 100 = 2400

Đề sai rồi bn, sao lại 1/1/3 được

có thể đó là hỗn số thì sao hả princess angel

   2 x 3 x 12 + 4 x 6 x 42 + 8 x 27 x 3

= 2 x 12 x 3 + 4 x 6 x 42 + 8 x 3 x 27

= 24 x 3 + 24 x 42 + 24 x 27

= 24 x ( 3 + 42 + 27 )

= 24 x 72

= 1728

2x3x12+4x6x42+8x27x3

=2x3x4x3+4x2x3x42+4x2x27x3

=2x3x4x(3+42+27)

=24x72

=1728

  2 x 3 x 12 + 4 x 6 x 42 + 8 x 27 x 3

= 2 x 3 x 12 + 2 x 2 x 6 x 42 + 2 x 4 x 27 x 3

= 2 x 36 + 2 x 504 + 2 x 324

= 2 x ( 36 + 504 + 324 )

= 2 x 864 = 1728 .

2 x 31 x 12 + 4 x 6 x 42 + 8 x 27 x 3

= 2 x 31 x 4 x 3 + 4 x 2 x 3 x 42 + 2 x 4 x 3 x 27

= [2 x 3 x 4] x (31 + 42 + 27)

= 24 x 100

= 2400 

\(P=\frac{3^9.3^{20}.3^8}{3^{24}.2^6.343}\)

\(\Leftrightarrow P=\frac{3^{37}}{3^{24}.2^6.3^5}\)

\(\Leftrightarrow P=\frac{3^{37}}{3^{29}.2^6}\)

\(\Leftrightarrow P=\frac{3^8}{2^6}\)

a: \(=\dfrac{7\left(145+55\right)}{6\left(315+35\right)}=\dfrac{7}{6}\cdot\dfrac{200}{350}=\dfrac{7}{6}\cdot\dfrac{4}{7}=\dfrac{2}{3}\)

2: \(=\dfrac{-2}{75}+\dfrac{5}{39}=\dfrac{33}{325}\)

3: \(=\dfrac{6}{11}\left(\dfrac{4}{9}+\dfrac{5}{9}\right)=\dfrac{6}{11}\)

4: \(=\dfrac{7}{19}\left(\dfrac{5}{13}+\dfrac{8}{13}-1\right)=-2\cdot\dfrac{7}{19}=-\dfrac{14}{19}\)

5: \(=\dfrac{2}{7}\left(\dfrac{4}{23}-\dfrac{27}{23}+1\right)=0\)

6: \(=\dfrac{3}{8}\left(\dfrac{3}{7}+\dfrac{4}{7}\right)+\dfrac{11}{8}=\dfrac{3}{8}+\dfrac{11}{8}=\dfrac{14}{8}=\dfrac{7}{4}\)