Respostas

2014-07-15T23:43:59-03:00
Baskhara = 2² - 4x1x-8
Baskhara= 4 + 32
Baskhara= 36

x'= 8 + 6/ 2 = 7
x''= 8 - 6/ 2 = 1
1 5 1
2014-07-15T23:49:01-03:00
X²+2x-8=0

Δ=4 + 32= 36

x¹= (-2+6) / 2= 2
x²= (-2-6) / 2= -4

(2)² + 2.(2) -8=0    
4 +4 -8=0
0=0 (v) 

ou

(-4)² + 2.(-4) -8=0
16 -8 -8=0
0=0 (v)
2 2 2