Question

ENCONTRAR AS RAÍZES

a) 3x²+4x-4=0

b) 5x²+12x+4=0

c) 4x²-20x+9=0

d) 12x²-7x+1=0

Por favor, me ajudem! Tô desesperada. trabalho para amanhã!

Answer 1

a) 3x² + 4x - 4 = 0

delta = b² - 4.a.c


a = 3
b = 4
c = -4

delta = 4² - 4.3.(-4)
delta = 16 + 48
delta = 64

x = -b ± √delta/2.a

x = -4 ± √64/2.3

x = -4 ± 8/6

x = -4 - 8/6 = -12/6 = -2

x = -4 + 8/6 = 4/6 = 2/3

S={ -2, 2/3 }
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b) 5x² + 12x + 4 = 0


a = 5
b = 12
c = 4


delta = 12² - 4.5.4
delta = 144 - 80
delta = 64


x = -12 ± √64/2.5

x = -12 ± 8/10

x = -12 - 8/10 = -20/10 = -2

x = -12 + 8/10 = -4/10 = -2/5


S={ -2, -2/5 }
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c) 4x² - 20x + 9 = 0

a = 4
b = -20
c = 9


delta = (-20)² - 4.4.9
delta = 400 - 144
delta = 256


x = -(-20) ± √256/2.4

x = 20 ± 16/8

x = 20 - 16/8 = 4/8 = 1/4

x = 20 + 16/8 = 36/8 = 9/4


S={ 1/4, 9/4 }
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d) 12x² - 7x + 1 = 0

a = 12
b = -7
c = 1

delta = (-7)² - 4.12.1
delta = 49 - 48
delta = 1


x = -(-7) ± √1/2.12

x = 7 ± 1/24

x = 7 - 1/24 = 6/24 = 1/4

x = 7 + 1/24 = 8/24 = 1/3


S={ 1/4, 1/3 }





☆Espero ter ajudado! tmj