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2014-08-05T20:09:41-03:00
A)  x^{2} + x - 6 = 0
Δ = 1 - 4.1.(-6)
Δ = 1 + 24  Δ = 25

x =  \frac{-1 +-5}{2}
x1 =  \frac{4}{2} = 2
x2 =  \frac{-6}{2} = -3

S= {2, -3}

b)  x^{2} + 4x - 5 = 0
Δ = 16 - 4.1.(-5)
Δ = 16 + 20  Δ= 36

x =  \frac{-4 +-6}{2}
x1 =  \frac{2}{2} = 1
x2 =  \frac{-10}{2} = -5

S = {1,5}

c)  2x^{2} - 9x + 4 = 0
Δ = 81 - 4.2.4
Δ = 81 - 32  Δ = 49

x =  \frac{9 +- 7}{2}
x1 =  \frac{16}{4} = 4
x2 =  \frac{2}{4}  \frac{1}{2}

S = {4, \frac{1}{2} }

d)  x^{2} - 10x + 24 = 0
Δ = 100 - 4.1.24
Δ = 100 - 96  Δ = 4

x =  \frac{10 +- 2}{2}
x1 =  \frac{12}{2} = 6
x2 =  \frac{8}{2} = 4

S = {6,4}
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