Question

7x-3y=6 2x=y+3 como resolve por escalonamento?

Answer 1

$\Large\boxed{\begin{array}{l}\begin{cases}\sf 7x-3y=6\\\sf 2x=y+3\end{cases}\\\\\begin{cases}\sf 7x-3y=6\cdot\bigg(-\dfrac{2}{7}\bigg)\\\sf 2x-y=3\end{cases}\\\\\begin{cases}\sf7x-3y=6\\\sf-\dfrac{1}{7}y=\dfrac{9}{7}\end{cases}\\\\\sf -\dfrac{1}{\backslash\!\!\!7}y=\dfrac{9}{\backslash\!\!\!7}\cdot(-1)\\\sf y=-9\\\sf 7x-3y=6\\\sf 7x-3\cdot(-9)=6\\\sf 7x+27=6\\\sf 7x=6-27\\\sf 7x=-21\\\sf x=-\dfrac{21}{7}\\\\\sf x=-3\\\sf S=\{-3,-9\}\end{array}}$