Question

Considere a equaçao x2-4x-7=0 sejam x1 e x2 suas raízes.Entao (x1)2+(x2)2

a)1 

b)2

c)3

d)30

e)31

Answer 1

x1= (4+√44)/2 = 2+√11
x2= (4-√44)/2 =  2-√11

x1²+x2²= 4+11+4√11 + 4+11-4√11 = 8+22 = 30   (D)