a: \(\dfrac{1}{x-1}+\dfrac{2}{3}\left(\dfrac{3}{4}-\dfrac{6}{5}\right)=\dfrac{5}{2x-2}\)
=>\(\dfrac{1}{x-1}-\dfrac{5}{2x-2}=-\dfrac{2}{3}\left(\dfrac{3}{4}-\dfrac{6}{5}\right)\)
=>\(\dfrac{-3}{2\left(x-1\right)}=-\dfrac{2}{3}\cdot\dfrac{3}{4}+\dfrac{2}{3}\cdot\dfrac{6}{5}\)
=>\(-\dfrac{3}{2\left(x-1\right)}=\dfrac{-1}{2}+\dfrac{4}{5}=\dfrac{3}{10}\)
=>2(x-1)=-10
=>x-1=-5
=>x=-4(nhận)
b: \(\dfrac{9}{15}x+15\dfrac{13}{15}x-20\dfrac{7}{15}x=12\)
=>\(x\left(\dfrac{9}{15}+15+\dfrac{13}{15}-20-\dfrac{7}{15}\right)=12\)
=>\(x\left(1-5\right)=12\)
=>-4x=12
=>x=-3
c:
\(720:\left[41-\left(2x-5\right)\right]=2^3\cdot5\)
=>\(41-\left(2x-5\right)=\dfrac{720}{8\cdot5}=\dfrac{720}{40}=18\)
=>2x-5=41-18=23
=>2x=28
=>\(x=\dfrac{28}{2}=14\)
d: 6(x+11)-7(2-x)=26
=>6x+66-14+7x=26
=>13x+52=26
=>13x=-26
=>x=-2
