Question

se 3x+y=6 e x+10y=31, o valor de x e igual a :
a)6 b)3 c)4 d)1

Answer 1

$\left \{ {{3x+y=6} \atop {x+10y=31}} \right.$

$3x+y=6 \\ \\ y=6-3x \\ \\ x+10y=31 \\ \\ x+10(6-3x)=31 \\ \\ x+60-30x=31 \\ \\ -29x=-29 \\ \\ x=1$

letra d