Question

Resolva o seguinte sistema usando o método indicado:
{2x-y=0
x-3y=-30
método comparação ​

Answer 1

$\boxed{\begin{array}{l}\begin{cases}\sf2x-y=0\\\sf x-3y=-30\end{cases}\\\\\begin{cases}\sf 2x=y\\\sf x=3y-30\end{cases}\\\\\begin{cases}\sf x=\dfrac{y}{2}\\\\\sf x=3y-30\end{cases}\\\\\sf 3y-30=\dfrac{y}{2}\\\sf 2\cdot(3y-30)=y\\\sf6y-60=y\\\sf 6y-y=60\\\sf 5y=60\\\sf y=\dfrac{60}{5}\\\\\sf y=12\\\\\sf x=\dfrac{y}{2}\\\\\sf x=\dfrac{12}{2}\\\\\sf x=6\\\sf S=\{6,12\}\end{array}}$