Question

Resolva os sistemas :

{X/5 = Y/2
X+Y=84

Answer 1

$\begin{cases} \dfrac{x}{5} = \dfrac{y}{2} \\\\ x+y=84\end{cases}\\\\\\\\ x+y=84\to~~x=-y+84\\\\\\\\ \dfrac{x}{5} = \dfrac{y}{2}\to~~ \dfrac{-y+84}{5} = \dfrac{y}{2}\to~~multiplique~~cruzado:\\\\ -2y+168=5y\to~~ 168=5y+2y\to~~168=7y\to~~ \dfrac{168}{7} =y\to \\\\ \large\boxed{y=24}\\\\\\\\x=-y+84\to~~x=-24+84\to~~ \large\boxed{x=60} \\\\\\\\\\ \Large\boxed{\boxed{S=\{60~;~24\}}}$