Bài 1
a, \(=-\dfrac{11}{4}+3\left(\dfrac{2}{9}+\dfrac{7}{12}\right)+\dfrac{1}{3}=-\dfrac{11}{4}+3\left(\dfrac{8+21}{36}\right)+\dfrac{1}{3}\)
\(=-\dfrac{11}{4}+\dfrac{29}{12}+\dfrac{1}{3}=\dfrac{-33+29+4}{12}=0\)
b, \(11x-15+21x-30x+45-x-10=-x-1\)
\(\Leftrightarrow x+20=-x-1\Leftrightarrow2x=-21\Leftrightarrow x=-\dfrac{21}{2}\)