Question

resolva os sistemas
a) 2x+-y=-4
x+y=4

b) x+y=8
2x-y=1

Answer 1

$b) \\ \\ \left \{ {{x+y=8} \atop {2x-y=1}} \right. \\ 3x = 9 \\ \\ x= 9/3 \\ x = 3 \\ \\ x + y = 8 \\ 3 + y = 8 \\ y = 8 - 3 \\ y = 5 \\ \\ resposta (3,5)$