a) \(\dfrac{9}{8}+\dfrac{3}{8}:x=0,25\\ < =>\dfrac{9}{8}+\dfrac{3}{8}:x=\dfrac{1}{4}\\ =>\dfrac{3}{8}:x=\dfrac{1}{4}-\dfrac{9}{8}=-\dfrac{7}{8}\\ =>x=\dfrac{\dfrac{3}{8}}{-\dfrac{7}{8}}=-\dfrac{3}{7}\)
b) \(\left(\dfrac{2x}{5}-1\right):\left(-5\right)=\dfrac{1}{7}\\ =>\dfrac{2x}{5}-1=\dfrac{1}{7}.\left(-5\right)=-\dfrac{5}{7}\\ =>\dfrac{2x}{5}=-\dfrac{5}{7}+1=\dfrac{2}{7}\\ =>2x=\dfrac{2}{7}.5=\dfrac{10}{7}\\ =>x=\dfrac{\dfrac{10}{7}}{2}=\dfrac{5}{7}\)
\(\dfrac{9}{8}+\dfrac{3}{8}:x=0,25\)
\(\Rightarrow\dfrac{9}{8}+\dfrac{3}{8}:x=\dfrac{1}{4}\)
\(\Rightarrow\dfrac{3}{8}:x=\dfrac{1}{4}-\dfrac{9}{8}\)
\(\Rightarrow\dfrac{3}{8}:x=\dfrac{-7}{8}\)
\(\Rightarrow x=\dfrac{3}{8}:\dfrac{-7}{8}\)
\(\Rightarrow x=\dfrac{-3}{7}\)
