bài 1 :
a)\(\dfrac{3}{7}\) + ( -\(\dfrac{5}{2}\) ) + ( \(\dfrac{-3}{5}\) ) b) ( -\(\dfrac{4}{3}\) ) + (-\(\dfrac{2}{5}\) ) + (- \(\dfrac{3}{2}\) )
c) \(\dfrac{4}{5}\)- ( \(\dfrac{-2}{7}\) ) - ( \(\dfrac{7}{10}\) ) d ) \(\dfrac{2}{3}\) - [(-\(\dfrac{4}{7}\) ) - ( \(\dfrac{1}{2}\) + \(\dfrac{3}{8}\) )]
bài 2 : tìm x , biêt
a) x + \(\dfrac{1}{3}\) = \(\dfrac{3}{4}\) ; b) x- \(\dfrac{2}{5}\) = \(\dfrac{5}{7}\)
c) -x - \(\dfrac{2}{3}\) = - \(\dfrac{6}{7}\) d) \(\dfrac{4}{7}\) -x = \(\dfrac{1}{3}\)
( mai nộp bài rôi ai giúp vs )
Bài 1
a.\(\dfrac{3}{7}+(-\dfrac{5}{2})+(\dfrac{-3}{5})=-\dfrac{187}{70}\)
b.\((-\dfrac{4}{3})+(-\dfrac{2}{5})+(-\dfrac{3}{2})=-\dfrac{97}{30}\)
c.\(\dfrac{4}{5}-(-\dfrac{2}{7})-\dfrac{7}{10}=\dfrac{27}{70}\)
d.\(\dfrac{2}{3}-\left[(-\dfrac{4}{7})-(\dfrac{1}{2}+\dfrac{3}{8}\right]=\dfrac{2}{3}+\dfrac{81}{56}=\dfrac{355}{168}\)
Bài 2
a.\(x+\dfrac{1}{3}=\dfrac{3}{4}\)
\(x=\dfrac{5}{12}\)
b.\(x-\dfrac{2}{5}=\dfrac{5}{7}\)
\(x=\dfrac{39}{35}\)
c.\(-x-\dfrac{2}{3}=-\dfrac{6}{7}\)
\(-x=-\dfrac{4}{21}\)
\(x=\dfrac{4}{21}\)
d.\(\dfrac{4}{7}-x=\dfrac{1}{3}\)
\(x=\dfrac{5}{21}\)
Xong r đó,mỏi hết tay.