Question

Raízes reais das equações 5x2-3x-2=0, x2-2x-8=0

Answer 1

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5x²-3x-2=0

a=5
b=-3
c=-2

Δ=b²-4ac
Δ=(-3)²-4(5)(-2)
Δ=9+40
Δ=49

x=(-b±√Δ)/2a=[-(-3)±√49)/10]=(3±7)/10

x'=(3+7)/10=10/10=1
x"=(3-7)/10=-4/10=-2/5

S={-2/5,1}

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x²-2x-8=0

a=1
b=-2
c=-8

Δ=b²-4ac
Δ=(-2)²-4(1)(-8)
Δ=4+32
Δ=36

x=[-(-2)±√36]/2=(2±6)/2

x'=(2+6)/2=8/2=4
x"=(2-6)/2=-4/2=-2

S={-2,4}