thank you bạn nha,mk chỉ muốn dc tặng socola thui à

3^x=27.81

27.81=3³.3⁴=3³⁺⁴

=3⁷

=>x=7

k nha

3^x = 27.81

3^x = 3³ . 3⁴

3^x = 3³⁺⁴

3^x = 3⁷

x = 7

a)\(\frac{1}{3}+\frac{2}{3}x=\frac{1}{4}\)

\(\Rightarrow\frac{2}{3}x=\frac{1}{4}-\frac{1}{3}\)

\(\Rightarrow\frac{2}{3}x=-\frac{1}{12}\)

\(\Rightarrow x=-\frac{1}{12}:\frac{2}{3}\)

\(\Rightarrow x=-\frac{1}{8}\)

b)\(\left|3x+1\right|-17=-12\)

\(\Rightarrow\left|3x+1\right|=5\)

\(\Rightarrow\orbr{\begin{cases}3x+1=5\\3x+1=-5\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}3x=4\\3x=-6\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{4}{3}\\x=-2\end{cases}}\)

a, 1/3 \(+\)2/3 x \(=\)1/4 

\(\Rightarrow\)2/3x \(=\)1/4 \(-\)1/3

\(\Rightarrow\)2/3 x \(=\)\(\frac{-1}{12}\)

\(\Rightarrow\)x \(=\)\(\frac{-1}{12}\)\(\div\)\(\frac{2}{3}\)

\(\Rightarrow\)x \(=\)\(\frac{-1}{12}\)\(\times\)\(\frac{2}{3}\)

\(\Rightarrow\)x \(=\)\(\frac{-1}{18}\)

b, \(|\)3x \(+\)1\(|\)\(-\)17 \(=\)-12

\(\Rightarrow\)\(|\)3x \(+\)1\(|\)\(=\)-12 \(+\)17

\(\Rightarrow\)\(|\)3x \(+\)1\(|\)\(=\)5 

\(\Rightarrow\)3x \(+\)1 \(=\)5 ;  3x \(+\)1\(=\)-5

\(\Rightarrow\)3x \(=\)5 \(-\)1 ;  3x \(=\)-5 \(-\)1

\(\Rightarrow\)3x \(=\)4 ;   3x \(=\)-6

\(\Rightarrow\)x \(=\)4 : 3 ;   x \(=\)-6 : 3

\(\Rightarrow\)x \(=\)\(\frac{4}{3}\);    x \(=\)-2

\(3\) \(\times\)\(2^3\)\(+\)\(|\)\(5\)\(-\)\(x\)\(|\)\(-4\times5^2\)\(=80\)

\(\Rightarrow\)\(3\times8+|5-x|-4\times25=80\)

\(\Rightarrow24+|5-x|-100=80\)

\(\Rightarrow|5-x|=80-24+100\)

\(\Rightarrow|5-x|=156\)

\(\Rightarrow5-x=156;5-x=-156\)

\(\Rightarrow x=5-156;x=5-(-156)\)

\(\Rightarrow x=-151;x=201\)

Phan k hai kho tho dau bai : Dem nay bac khong ngu

ko hiểu phan nhưng bài đêm nay bác ko ngủ mk học qua r

[32-(-15)]+[-12-45]-[15+(-41)-12] = 28 

'' hok tốt ''

\(\left[32-\left(-15\right)\right]+\left[-12-45\right]-\left[15+\left(-41\right)-12\right]\)

\(=32+15-12-45-15+41+12\)

\(=32-45+41+\left(15-15\right)+\left(12-12\right)\)

\(=28\)

\(\frac{2.\left(-13\right).9.10}{-3.4.\left(-5\right).26}=\frac{2.\left(-13\right).\left(-3\right).\left(-3\right).\left(-5\right).\left(-2\right)}{-3.2.2.\left(-5\right).\left(-13\right).\left(-2\right)}=\frac{-3}{2}\)

Bạn tự trực tiêu các số bằng nhau nha

Chúc học tốt!

\(\frac{2.\left(-13\right).9.10}{-3.4.\left(-5\right).26}\)

\(=\frac{1.\left(-1\right).3.2}{-1.2.\left(-1\right).2}\)

\(=\frac{-6}{4}=\frac{-3}{2}\)

Vậy phân số \(\frac{2.\left(-13\right).9.10}{-3.4.\left(-5\right).26}\) rút gọn là \(\frac{-3}{2}\)