Resposta :
[tex]\frac{X. Z}{Y}[/tex]
[tex]\frac{\frac{2}{3} . \frac{9}{5}}{\frac{3}{5}} = \frac{X . \frac{1}{4}}{\frac{7}{8}} [/tex]
[tex]\frac{\frac{18}{15}}{\frac{3}{5}} = \frac{\frac{X}{4}}{\frac{7}{8}} [/tex]
[tex]\frac{18}{15} . \frac{5}{3} = \frac{X}{4} . \frac{8}{7} [/tex]
[tex]\frac{6}{3} = \frac{2X}{7}[/tex]
[tex]\frac{6 . 7}{3 . 2} = X}[/tex]
[tex]X = 7[/tex]
[tex]\frac{\frac{2}{3} . \frac{9}{5}}{\frac{3}{5}} = \frac{X . \frac{1}{4}}{\frac{7}{8}} [/tex]
[tex]\frac{\frac{18}{15}}{\frac{3}{5}} = \frac{\frac{X}{4}}{\frac{7}{8}} [/tex]
[tex]\frac{18}{15} . \frac{5}{3} = \frac{X}{4} . \frac{8}{7} [/tex]
[tex]\frac{6}{3} = \frac{2X}{7}[/tex]
[tex]\frac{6 . 7}{3 . 2} = X}[/tex]
[tex]X = 7[/tex]