Question

x/y = 2/5, sabendo-se x+y=25

Answer 1

Olá, isolando X na primeira, temos:

x = 2y/5

Substituindo na segunda.

x + y = 25
2y/5 + y = 25
7y/5 = 25
7y = 25*5
y = 125/7

Achando x

x = 2y/5
x = 2*(125/7)/5
x = 250/7 * 1/5
x = 250/35
x = 50/7

Answer 2

$( \frac{x}{y} = \frac{2}{5} \\ (x + y = 25$
$( \frac{x}{y} = \frac{2}{5} \\ (x = 25 - y$

$\frac{25 - y}{y} = \frac{2}{5}$
$y = \frac{125}{7}$
$x = 25 - \frac{125}{7}$
$x = \frac{50}{7}$

R: ( 50/7 e 125/7 )