2 bạn nhé

là trâu,bò và ốc

:))

\(a,\frac{20^{12}\cdot6^{14}}{8^{13}\cdot15^{12}}\)

\(=\frac{5^{12}\cdot2^{24}\cdot2^{14}\cdot3^{14}}{2^{39}\cdot3^{12}\cdot5^{12}}\)

\(=\frac{5^{12}\cdot2^{38}\cdot3^{14}}{2^{39}\cdot3^{12}\cdot5^{12}}=\frac{3^2}{2}=\frac{9}{2}\)

\(b,\frac{45^{12}\cdot10^{14}}{18^{13}\cdot25^{12}}\)

\(=\frac{5^{12}\cdot3^{24}\cdot2^{14}\cdot5^{14}}{2^{13}\cdot3^{26}\cdot5^{24}}\)

\(=\frac{5^{26}\cdot3^{24}\cdot2^{14}}{2^{13}\cdot3^{26}\cdot5^{24}}=\frac{5^2\cdot2}{3^2}=\frac{50}{9}\)

\(c,\frac{18^{12}\cdot27^8}{6^8\cdot3^{40}}\)

\(=\frac{2^{12}\cdot3^{24}\cdot3^{24}}{2^8\cdot3^8\cdot3^{40}}\)

\(=\frac{2^{12}\cdot3^{48}}{2^8\cdot3^{48}}=2^4=16\)

\(d,\frac{12^{14}\cdot9^{18}}{8^9\cdot27^{17}}\)

\(=\frac{3^{14}\cdot2^{28}\cdot3^{36}}{2^{27}\cdot3^{51}}\)

\(=\frac{3^{50}\cdot2^{28}}{2^{27}\cdot3^{51}}=\frac{2}{3}\)

làm hơi tắt nên chịu khó hiểu

\(\frac{2}{3}x-1\frac{2}{5}=\frac{1}{2}x+0,0\left(3\right)\)

\(\Rightarrow\frac{2}{3}x-\frac{1}{2}x=\frac{7}{5}+\frac{1}{33}=\frac{231}{165}+\frac{5}{165}=\frac{236}{165}\)

\(\Rightarrow\frac{1}{6}x=\frac{236}{165}\Rightarrow x=\frac{236}{165}.6=\frac{1416}{165}=8\frac{96}{165}\)

\(\frac{a+c}{b+d}=\frac{2a-c}{2b-d}\)

Áp dụng .... ta có:

\(\frac{a+c}{b+d}=\frac{2a-c}{2b-d}=\frac{a+c+2a-c}{b+d+2b-d}=\frac{3a}{3b}=\frac{a}{b}\)  

Ta có \(\frac{a+c}{b+d}=\frac{2a-c}{2b-d}=\frac{a}{b}\)

Áp dụng tính chất dãy tỉ số bằng nhau ta có:

\(\frac{a+c}{b+d}=\frac{2a-c}{2b-d}=\frac{a}{b}=\frac{a+c-2a+c+a}{b+d-2b+d+b}=\frac{2c}{2d}=\frac{c}{d}\)

Vậy \(\frac{a}{b}=\frac{c}{d}\)

Trong đó không có 3 điểm thẳng hàng nhé

\(a)=\frac{7}{25}+\frac{4}{13}-\frac{5}{2}+\frac{18}{25}-\frac{17}{13}\)

\(=1-1-\frac{5}{2}\)

\(=-\frac{5}{2}\)

cái này bạn bấm máy tính là ra mà 

bấm máy tính là ra