Question

Mark the correct alternative in each of the following:

If $-\frac{3}{4}=\frac{6}{x}$, then x =

(a) −8 (b) 4 (c) −4 (d) 8

Answer 1

$$\begin{gathered} -\frac{3}{4}=\frac{6}{x} \\ \Rightarrow -3\times x=6\times 4\left(\frac{a}{b}=\frac{c}{d}\Rightarrow ad=bc\right) \\ \Rightarrow -3x=24 \\ \Rightarrow \frac{-3x}{-3}=\frac{24}{-3}\left(\mathrm{Dividing}\mathrm{both}\mathrm{sides}\mathrm{by}-3\right) \\ \Rightarrow x=-8 \end{gathered}$$

Hence, the correct answer is option (a).