Question

2X+6Y=10
4X-2Y=-1 Pf Ajudem?

Answer 1

Oi,

multiplique a equação I por -2 e some com a equação II:

$+\begin{cases}-4x-12y=-20~~(I)\\ ~~4x-2y=-1~~(II) \end{cases}\\ ~~~~------\\ ~~~~~~~~~~~-14y~~=~~-21\\\\ ~~~~~~~~~~~~y= \dfrac{-21}{-14}\\\\ ~~~~~~~~~~~~~~~y= \dfrac{7}{2}\\\\\\ 4x-2y=-1\\\\ 4x-2\cdot \dfrac{7}{2}=-1\\\\ 4x-7=-1\\ 4x=-1+7\\ 4x=6\\\\ x= \dfrac{6}{4}= \dfrac{3}{2}\\\\\\ \large\boxed{\boxed{S=\left\{\left( \dfrac{3}{2},~ \dfrac{7}{2}\right)\right\}}}$

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