Question

..............
3x-y=15
x+4y=2y

Answer 1

Resposta:

$x=\frac{30}{7} ,y=\frac{-15}{7}$

Explicação passo-a-passo:

$\left \{ {3x-y=15 \atop x+4y=2y} \right. \\\left \{ {3x-y=15 \atop x=2y-4y} \right.\\\left \{ {3x-y=15 \atop x=-2y} \right.\\\left \{ {3(-2y)-y=15 \atop x=-2y} \right.\\\left \{ {-6y-y=15 \atop x=-2y} \right.\\\left \{ {-7y=15 \atop x=-2y} \right.\\\left \{ {y=\frac{-15}{7}\atop x=-2y} \right.\\\left \{ {y=\frac{-15}{7}\atop x=\frac{30}{7} } \right.$