a.
\(\dfrac{6}{13}-0,5.x=\dfrac{-3}{2}\)
\(\dfrac{6}{13}-\dfrac{1}{2}.x=-\dfrac{3}{2}\)
\(\dfrac{1}{2}.x=\dfrac{6}{13}-\dfrac{-3}{2}\)
\(\dfrac{1}{2}.x=\dfrac{51}{26}\)
\(x=\dfrac{51}{26}:\dfrac{1}{2}\)
\(x=\dfrac{51}{13}\)
b.
\(2,8-5.\left(x-10\right)=-\dfrac{3}{4}\)
\(2,8-5.\left(x-10\right)=-0,75\)
\(5.\left(x-10\right)=2,8-\left(-0,75\right)\)
\(5\left(x-10\right)=3,55\)
\(x-10=3,55:5\)
\(x-10=0,71\)
\(x=0,71+10\)
\(x=10,71\)
c.
\(210:x-\dfrac{1}{2}=20,5\)
\(210:x-0,5=20,5\)
\(210:x=20,5+0,5\)
\(210:x=21\)
\(x=210:21\)
\(x=10\)
d.
\(\dfrac{2}{3}x-\dfrac{3}{4}x=\left(-\dfrac{5}{12}\right).\dfrac{8}{15}\)
\(\left(\dfrac{2}{3}-\dfrac{3}{4}\right).x=-\dfrac{2}{9}\)
\(-\dfrac{1}{12}.x=\dfrac{2}{9}\)
\(x=\dfrac{2}{9}:\left(-\dfrac{1}{12}\right)\)
\(x=-\dfrac{8}{3}\)
Giúp mình với aa (Giải chi tiết + nếu được thì thêm lời giải thích ở cuối bài làm giúp mình nha 
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