Question

Sistema de equações: Queeroo resposta completaa

-3x+4=14
4x-y=8

Answer 1

$\begin{cases}-3x+4y=14\\ 4x-y=8\end{cases}\\\\\\\\4x-y=8\to ~~ -y=-4x+8~(-1) \to ~~ y=4x-8\\\\ \\\\-3x+4y=14\to~ -3x+4(4x-8)=14\to~-3x+16x-32=14\to\\\\ -3x+16x=14+32\to~~13x=46\to~~ \boxed{x= \frac{46}{13}}\\\\\\\\ y=4x-8\to~~ y=4\left( \dfrac{46}{13}\right)-8\to~~ y= \dfrac{184}{13}-8\to~~y= \dfrac{184-104}{13}\to\\\\ \boxed{y= \dfrac{80}{13}}\\\\\\\\\\ \large\boxed{\boxed{S=\left\{ \dfrac{46}{13}~;~ \dfrac{80}{13} \right\}}}$