Bài 1:
a) \(=\dfrac{4}{9}-\dfrac{1}{4}-1=-\dfrac{29}{36}\)
b) \(=-\dfrac{11}{18}:\dfrac{31}{36}=-\dfrac{11}{18}.\dfrac{36}{31}=-\dfrac{22}{31}\)
Bài 2:
a) \(\Rightarrow x=\dfrac{2}{5}+\dfrac{5}{7}=\dfrac{39}{35}\)
b) \(\Rightarrow\left|2x+\dfrac{1}{2}\right|=\dfrac{7}{6}\)
\(\Rightarrow\left[{}\begin{matrix}2x+\dfrac{1}{2}=\dfrac{7}{6}\\2x+\dfrac{1}{2}=-\dfrac{7}{6}\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{3}\\x=-\dfrac{5}{6}\end{matrix}\right.\)
Bài 3:
\(27^{11}=\left(3^3\right)^{11}=3^{33}>3^{32}=\left(3^4\right)^8=81^8\)