Respostas

2013-07-03T15:55:13-03:00

x²+y²=13

x-y=1

*x=1+y

*(1+y)²+y²=13

1+2y+y²+y²=13

2y²+2y+1=13

2y²+2y-12=0

delta=4+96

delta=100

y=(-2+/-10)/4

y=-3

y=2

*x-y=1

x=1+y

x=1-3

x=-2

x=1+2

x=3

3 5 3