Question

Answer 1

\(1.\)

\(a.\left(85,5+4,5\right)-\left(12,02+7,98\right)\)

\(=90+20=110\)

\(b.\dfrac{-5}{2}:\left(\dfrac{3}{4}-\dfrac{1}{2}\right)\)

\(=-\dfrac{5}{2}:\dfrac{1}{4}=-10\)

\(2.\)

\(a.x+\dfrac{-7}{15}=-1\dfrac{1}{20}\)

   \(x+\dfrac{-7}{15}=\dfrac{-19}{20}\)

           \(x=\dfrac{-19}{20}-\dfrac{-7}{15}\)

           \(x=\dfrac{-29}{60}\)

\(b.\dfrac{1}{2}+\dfrac{3}{5}\left(x-2\right)=\dfrac{1}{5}\)

           \(\dfrac{3}{5}\left(x-2\right)=\dfrac{1}{5}-\dfrac{1}{2}\)

           \(\dfrac{3}{5}\left(x-2\right)=\dfrac{-3}{10}\)

           \(x-2=\dfrac{-3}{10}:\dfrac{3}{5}\)

           \(x-2=\dfrac{-1}{2}\)

           \(x=\dfrac{-1}{2}+2\)

           \(x=\dfrac{3}{2}\)