Question

A soma de dois numeros e igual a 15 a diferença entre eles e igual a 9?

Answer 1

Resposta:

12 e 3

{x+y=15

{x-y=9

2x = 24

x=24/2

x=12

y = 15 - x

y = 15 - 12

y = 3

Answer 2

$\left \{ {{x+y=15} \atop {x-y=9}} \right. \\2x=24\\x=12\\12+y=15\\y=3$