a, Ta có : \(\dfrac{x}{4}\)= \(\dfrac{16}{128}\)
\(\Rightarrow\)4 . 16 = x . 128
\(\Rightarrow\) x = (4 . 16 ) : 128
\(\Rightarrow\) x = \(\dfrac{1}{2}\)
b, Ta có : 1\(\dfrac{5}{6}\) = \(\dfrac{-x}{5}\)
\(\Leftrightarrow\dfrac{11}{6}\) = \(\dfrac{-x}{5}\)
\(\Rightarrow\)11 . 5 = 6 . ( \(-x\) )
\(\Rightarrow\)\(-x\) = (11. 5) : 6
\(\Rightarrow\) \(-x\) = \(\dfrac{-55}{6}\)
\(\Rightarrow\) \(x\) = \(\dfrac{55}{6}\)
c,Ta có : 4 , 25 : 8 = \(-3,5\) : x
\(\Rightarrow\) \(\dfrac{17}{32}\) = \(\dfrac{-3,5}{x}\)
\(\Rightarrow\) 17 . x = \(-3,5\) . 32
\(\Rightarrow\) x = ( \(-3,5\) . 32 ): 17
\(\Rightarrow\) x = \(\dfrac{-112}{17}\)
