Question

Answer 1

\(\dfrac{-7}{x}=\dfrac{-21}{x-34}\)

\(\Rightarrow-7\left(x-34\right)=-21x\)

\(-7x+238=-21x\)

\(-7x+21x=-238\)

14x=-238

x=-17

Answer 2

đk : x khác 0 ; 34

\(-7x+238=-21x\Leftrightarrow14x=-238\Leftrightarrow x=-17\)(tm) 

Answer 3

\(\Leftrightarrow\dfrac{-7\left(x-34\right)+21x}{x\left(x-34\right)}=0\\ \Leftrightarrow-7\left(x-34\right)+21x\\ \Leftrightarrow-7x+238+21x=0\\ \Leftrightarrow14x=-238\\ \Leftrightarrow x=-17\)

Answer 4

`(-7)/x = (-21)/(x-34)`

`=> -7 . (x-34) = x.-21`

`=> -7x - (-238) = -21x`

`=> -7x + 21x = -238`

`=> (-7 + 21)x = -238`

`=> 14x = -238`

`=>    x  = -238 : 14`

`=>   x  = -17`