Question

determine x e y
x + y = 71
2x - y = 1​

Answer 1

Resposta:

$\left \{ {{x=24} \atop {y=47}} \right.$

Explicação passo a passo:

$\left \{ {{x+y=71} \atop {2x-y=1}} \right. \\\\\left \{ {{x=71-y} \atop {2x-y=1}} \right.\\\\2(71-y)-y=1\\\\142-2y-y=1\\\\142-3y=1\\\\142=1+3y\\\\3y=142-1\\\\3y=141\\\\y=\frac{141}{3}\\\\ y=47\\\\\\ x=71-y\\\\x=71-47\\\\x=24$