Question

si 7/8 = 28/x , luego 2x

Answer 1

Si Luego 2x = ? 

7/8 = 28/x 
7 * x = 28 * 8 
7x = 224..../:7 

x= 32 

2x = 2 * 32 = 64 

Answer 2

$\frac{7}{8}= \frac{28}{x} \ Aplicas \ la \ propiedad \ Fundamental \ de \ proporci \acute{o}n \\ \\ \frac{a}{b}= \frac{c}{d} \Longleftrightarrow a*d = b*c \\ \\ \frac{7}{8}= \frac{28}{x}\Longleftrightarrow 7*x = 28*8 \\ \\ \frac{7}{8}= \frac{28}{x}\Longleftrightarrow 7*x = 224 \\ \\ \frac{7}{8}= \frac{28}{x}\Longleftrightarrow x = \frac{224}{7} \\ \\\frac{7}{8}= \frac{28}{x}\Longleftrightarrow x = 32 \\ \\ Entonces \Longrightarrow 2*x = 2*32= 64$

Espero que te sirva, salu2!!!!