Respostas

  • Usuário do Brainly
2014-06-24T19:59:10-03:00
Irracional

√y =4-2-y
√y=2-y
(√y)²=(2-y)²
y=4-4y+y²

y² -5y +4=0

Δ=25-16=9
√Δ=3

x'= \frac{5+3}{2} = \frac{8}{2} =4

x"= \frac{5-3}{2} = \frac{2}{2} =1

verificação
√y +2+y=4

p/x=4
 √4 +2 +4 =4
2+2+4=4
8≠4


p/ x=1

√1 +2 +1=4
1+2+1=4
4=4

S={1}