cách 1: 

= 134x10

=1340

cách 2 :

=134x18-134x8

=1340

\(a,x-\dfrac{1}{4}=\dfrac{7}{2}.\dfrac{-3}{5}\\ \Rightarrow x-\dfrac{1}{4}=\dfrac{-21}{10}\\ \Rightarrow x=\dfrac{-21}{10}+\dfrac{1}{4}\\ \Rightarrow x=\dfrac{-37}{20}\\ b,\dfrac{x}{134}=\dfrac{9}{7}.\dfrac{5}{-11}\\ \Rightarrow\dfrac{x}{134}=\dfrac{-45}{77}\\ \Rightarrow x=\dfrac{-45}{77}.134\\ \Rightarrow x=\dfrac{-6030}{77}\)

\(x-\dfrac{1}{4}=\dfrac{7}{2}\cdot\dfrac{-3}{5}\)

\(x-\dfrac{1}{4}=\dfrac{-21}{10}\)

\(x=\dfrac{-21}{10}+\dfrac{1}{4}\)

\(x=\dfrac{-37}{20}\)

b ) \(\dfrac{x}{134}=\dfrac{9}{7}\cdot\dfrac{5}{-11}\)

      \(\dfrac{x}{134}=\dfrac{9}{7}\cdot\dfrac{-5}{11}\)

       \(\dfrac{x}{134}=\dfrac{-45}{77}\)

       \(x=\dfrac{-45}{77}\cdot134\)

       \(x=-\dfrac{6034}{77}\)

7,(42-x)=5³+134

7(42-x)=125+134

7(42-x)=259

42-x=259:7

42-x=37

x=42-37

x=5

tk tớ nha, tớ nhanh nhất

7( 42 - x ) = 5^3 + 134

7( 42 - x ) = 259

   42 - x    = 259 : 7

    42 - x = 37

           x = 42 - 37

           x = 5

   134 x 27 + 636 x 134 + 134 x 324 + 134 

= 134 x ( 27 + 636 + 324 + 1)

= 134 x 988

=132392

1111111111111111111111111111111111111111111111111111111111111111

138 x 97 + 138 x 3

Ghi cả cách trình bày nha mọi người

\(a,\dfrac{4}{15}:\dfrac{4}{7}< x< \dfrac{2}{5}\times\dfrac{10}{3}\\ \Leftrightarrow\dfrac{7}{15}< x< \dfrac{4}{3}\\ \Leftrightarrow x=1\)

\(b,\dfrac{3}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{9}{35}+\dfrac{8}{35}=\dfrac{17}{35}\)