Question

$\left \{ {{x=2y} \atop {2x-5y=3}} \right.$

Como resolver o sistema pela método da substituição?

Answer 1

$\begin{cases}x=2y\\2x-5y=3\end{cases}\\\\\\\\ Basta~~pegar~~o~~valor~~dado~~para~~x~~na~~1\° ~~equa{\c c}\~ao ~~e~~substituir\\ em~~x~~na~~2\°,~~afim~~de~~encontrar~~ y:\\\\\\ 2x-5y=3\to~~2.2y-5y=3\to~~ 4y-5y=3\to~~-y=3~(-1)\to\\\\ \large\boxed{y=-3} \\\\\\ Agora~~que~~encontrou~~y,~~volte ~~na~~1\°~~equa{\c c}\~ao ~~substitua ~~esse\\valor~~em~~y~~afim~~de~~encontrar~~x:\\\\\\ x=2y\to~~x=2.(-3)\to~~\large\boxed{x=-6}\\\\\\\\\\\\ \large\boxed{\boxed{S=\{-6~;~-3\}}}$