Question

$\left \{ {{x-y=20} \atop {x=4-y}} \right.$

Answer 1

Resposta:

x = 12

y = (-8)

Explicação passo a passo:

$\left \{ {{x-y=20} \atop {x=4-y}} \right. \\\\x-y=20\\\\4-y-y=20\\\\4-2y=20\\\\2-y=10\\\\2=10+y\\\\y=2-10\\\\\bold{y=(-8)}\\\\\\\\x=4-y\\\\x=4-(-8)\\\\x=4+8\\\\\bold{x=12}$