Question

x ao quadrado + y ao quadrado = 13
x-y=1

Answer 1

{x²+y²=13

{x - y=1 → x=y+1

(y+1)²+y²=13

y²+2y+1+y²=13

2y²+2y+1-13=0

2y²+2y-12=0 ÷(2)

y²+y-6=0

y²-2y+3y-6=0

y(y-2)+3(y-2)=0

(y-2)(y+3)=0

y-2=0 →y=2

y+3=0→y=-3

Se y=2

x=2+1=3

Se y=-3

x=-3+1=-2

S={(3,2), (-2,-3)}