Question

Sabendo que x+y=42, determine x e y na proporção x/y=5/9.

Answer 1

$\boxed{x=42-y}\\ \\ \frac{x}{y}=\frac{5}{9}\\ \\ \frac{42-y}{y}=\frac{5}{9}\\ \\ 5y=9(42-y)\\ \\ 5y=378-9y\\ \\ 14y=378\\ \\ \boxed{y=27}\\ \\ x=42-27\\ \\ \boxed{x=15}$