Bằng miệng
c, \(\dfrac{2}{3}\left(-3x-\dfrac{6}{5}\right)-\dfrac{5}{7}\left(\dfrac{49}{15}-14x\right)=-2\dfrac{1}{3}\)
<=> (-2x - \(\dfrac{4}{5}\)) - (\(\dfrac{7}{3}-10x\)) = -2\(\dfrac{1}{3}\)
<=> -2x - \(\dfrac{4}{5}-\dfrac{7}{3}+10x=-2\dfrac{1}{3}\)
<=> 8x - \(\dfrac{47}{15}=-\dfrac{64}{3}\)
<=> 8x = \(-\dfrac{91}{5}\)
<=> x = \(-\dfrac{91}{40}\)
@Nguyễn Gia Hân
b, \(\dfrac{3}{4}\left(x-\dfrac{8}{9}\right)-5\left(x-\dfrac{11}{15}\right)+\dfrac{1}{2}x=5\dfrac{1}{12}\)
<=> \(\left(\dfrac{3}{4}x-\dfrac{2}{3}\right)-\left(5x-\dfrac{11}{3}\right)+\dfrac{1}{2}x=5\dfrac{1}{12}\)
<=> \(\dfrac{3}{4}x-\dfrac{2}{3}-5x+\dfrac{11}{3}+\dfrac{1}{2}x=\dfrac{61}{12}\)
<=> \(-\dfrac{15}{4}x+3=\dfrac{61}{12}\)
<=> \(-\dfrac{15}{4}x=\dfrac{25}{12}\)
<=> x = \(-\dfrac{5}{9}\)
@Nguyễn Gia Hân
a, (\(\dfrac{2}{9}\)(6x - \(\dfrac{3}{4}\)) - 3(\(\dfrac{1}{4}x-\dfrac{1}{5}\)) = \(\dfrac{-8}{15}\)
<=> (\(\dfrac{4}{3}x-\dfrac{1}{6}\)) - (\(\dfrac{3}{4}x-\dfrac{3}{5}\)) = \(\dfrac{-8}{15}\)
<=> \(\dfrac{4}{3}x-\dfrac{1}{6}-\dfrac{3}{4}x+\dfrac{3}{5}=\dfrac{-8}{15}\)
<=> \(\dfrac{7}{12}x+\dfrac{13}{30}=\dfrac{-8}{15}\)
<=> \(\dfrac{7}{12}x=\dfrac{-8}{15}-\dfrac{13}{30}\)
<=> \(\dfrac{7}{12}x=-\dfrac{29}{30}\)
<=> x = \(-\dfrac{58}{35}\)
@Nguyễn Gia Hân