Cho $\dfrac{{15}}{x} = \dfrac{5}{7}$ thì giá trị $x$ là:

$x = 4$                          

$x\; = -4$                   

$x = 4$ hoặc $x = -4$            

$x = 0$

$\dfrac{{245}}{{100}}$             

$\dfrac{{245}}{{1000}}$                  

$\dfrac{{49}}{{500}}$               

$\dfrac{{49}}{{200}}$

$\dfrac{{12}}{6}\, = \,\dfrac{9}{8}\,$

$\dfrac{8}{6}\, = \,\dfrac{{12}}{9}\,$           

$\dfrac{6}{{12}}\, = \,\dfrac{8}{9}\,$           

$\dfrac{6}{8}\, = \,\dfrac{{12}}{9}\,$

$49$                            

$- 49$

$7$  và $- 7$

$7$    

$448,6$          

$448$

$450$

$448,58$        

$\,{\left( { - \,3} \right)^6}$                  

$\,{\left( { - \,3} \right)^2}$   

$\,{\left( { - \,3} \right)^8}$              

$\,{\left( { - \,3} \right)^5}$

$- \dfrac{5}{2}$                    

$- 1$

$- \dfrac{5}{4}$        

$- \dfrac{2}{5}$