\(x-\dfrac{3}{4}=\dfrac{1}{7}\\ \Rightarrow x=\dfrac{25}{28}\)
\(\left(-x+\dfrac{3}{5}\right)+\dfrac{13}{20}=\dfrac{5}{6}\\ \Leftrightarrow\left(-x+\dfrac{3}{5}\right)=\dfrac{11}{60}\\ \Leftrightarrow-x=\dfrac{11}{60}-\dfrac{3}{5}\\ \Rightarrow-x=-\dfrac{5}{12}\\ \Rightarrow x=\dfrac{5}{12}\)
x-3/4=1/7 (-x+3/5)+13/20=5/6
x = 1/7+3/4 -x+3/5 =5/6-13/20
x = 4/28+21/28 -x+3/5 =50/60-39/60
x = 25/28 -x+3/5 = 11/60
-x =11/60-3/5
-x =11/60-36/60
-x = -25/60