Câu 1 :
a, \(\dfrac{1}{2}\) + \(\dfrac{3}{4}\): \(\dfrac{-3}{5}\)= \(\dfrac{1}{2}\)+ \(\dfrac{3}{4}\) x \(\dfrac{-5}{3}\)= \(\dfrac{1}{2}\)+ \(\dfrac{-5}{4}\)=\(\dfrac{2}{4}\)+ \(\dfrac{-5}{4}\)= - \(\dfrac{3}{4}\)
Câu 1 :
b,\(\left|\dfrac{-5}{6}\right|\) - \(\dfrac{3}{10}\): \(\left(\dfrac{1}{2}-\dfrac{4}{5}\right)^2\)= \(\dfrac{5}{6}\) - \(\dfrac{3}{10}\): \(\left(\dfrac{1}{5}\right)^2\)= \(\dfrac{5}{6}\) - \(\dfrac{3}{10}\) x \(\dfrac{1}{10}\)= \(\dfrac{5}{6}\) - \(\dfrac{3}{100}\)= ...mình lười tính quá 
Câu 2:
a: \(x=\dfrac{3}{4}-\dfrac{2}{3}=\dfrac{9-8}{12}=\dfrac{1}{12}\)
