Respostas

2013-12-11T20:14:14-02:00
x² - 5 x + 4 = 0    
a = 1, b = -5, c = 4
Δ = b² - 4 a c
Δ = (-5)² - 4.1.4
Δ = 25 - 16
Δ = 9
x = (-b+/-√Δ)/2a
x = [-(-5)+/-√9]/2.1
x = (5+/-3)/2
x' = (5+3)/2 --> x' = 8/2 --> x' = 4
x" = (5-3)/2 --> x" = 2/2 --> x" = 1
S: {1;4}
2013-12-11T20:23:49-02:00
X² - 5x + 4 = 0
S =  5    x = 1
P = 4     x = 4
        ou
Δ = 25 - 4 . 4 . 1
Δ = 25 - 16
Δ = 9
x = 5 + - √9 / 2 . 1
x = 5 + 3 / 2
                         x = 4
x = 5 - 3 / 2
                         x = 1