Question

{x + y = 21
{x - y = -8
plmds

Answer 1

Resposta:

Explicação passo a passo:

x+y=21

x-y=-8

______

2x+0=13

2x=13

x=13/2

x+y=21

13/2+y=21

y=21-13/2

y=42/2-13/2

y=29/2