Respostas

2013-11-18T20:59:12-02:00
X²+2y²=18
x-y=-3 --> y = x+3

x²+2.(x+3)² = 18
x²+2.(x²+6x+9) = 18
x²+2x²+12x+18 = 18
3x²+12x = 0
3x(x+4) = 0
3x = 0 --> x = 0
x+4 = 0 --> x = -4

y = x+3
y = 0+3 --> y = 3
y = -4+3 --> y = -1

S:{(0,3);(-4,-1)}