Question

Tim x biet (7.13+8.13)÷(13/2-x)=39

Answer 1

(13.15):(13/2-x)=39

195:(13/2-x)=39

13/2-x=195:39

13/2-x=5

x=13/2-5

x=3/2

vậy x=3/2

Answer 2

Ta có: \(\left(7.13+8.13\right):\left(\frac{13}{2-x}\right)=39\)

         \(\Leftrightarrow\)\(\frac{\left(91+104\right).\left(2-x\right)}{13}=\)\(39\)

        \(\Leftrightarrow\) \(\frac{195.\left(2-x\right)}{13}=39\)

        \(\Leftrightarrow\)\(390-195x=39.13\)

        \(\Leftrightarrow\)\(390-195x=507\)

         \(\Leftrightarrow\)\(-195x=117\)

          \(\Leftrightarrow\)x=\(\frac{-117}{195}=\frac{-39}{65}\)