Respostas
Explicação passo-a-passo:
a) a=1 b=6 c=9
x² + 6x + 9 = 0
b) a=4 b=-6 c=2
4x² - 6x + 2 = 0
c) a=3 b=0 b=4
3x² + 4 = 0
d) a=4 b=0 c=-25
4x² - 25 = 0
e) a=-21 b=7 c=0
-21x² + 7x = 0
a) x²-12 x=0
x(x - 12) = 0
x = 0
(x - 12) = 0
x - 12 = 0
x = + 12
S[0,12]
b) x² - 1=0
x² = +1
x = ± √1
x = ± 1
S[-1 , 1]
c) x² -16=0
x² = + 16
x = ± √16
x = ± 4
S[- 4 , + 4]
d)5x²-3x=0
x(5x - 3) = 0
x = 0
(5x - 3) = 0
5x - 3 = 0
5x = +3
x = 3/5 ou 0,6
S[0, 3/5 ou 0,6]
e)x²+x=0
x(x + 1) = 0
x = 0
(x + 1) =0
x + 1 = 0
x = - 1
S[- 1, 0]
a) x²- 7x + 6 = 0
a = 1 b = - 7 c = + 6
Δ = b² -4.a.c
Δ = (-7)² - 4.(1).(+6)
Δ = 49 - 24
Δ = 25
x = - b ± √Δ
2.a
x = - (-7) ± √25
2.1
x = + 7 ± 5
2
x'= 7 + 5 = 12 = 6
2 2
x"= 7 - 5 = 2 = 1
2 2
S[1 , 6]
b) x² - x - 12 = 0
a = 1 b = - 1 c = - 12
Δ = b² -4.a.c
Δ = (-1)² - 4.(1).(-12)
Δ = 1 + 48
Δ = 49
x = - b ± √Δ
2.a
x = - (-1) ± √49
2.1
x = + 1 ± 7
2
x'= 1 + 7 = 8 = 4
2 2
x"= 1 - 7 = - 6 = - 3
2 2
S[-3 , 4]
c) x²- 3x- 28=0
a = 1 b = - 3 c = - 28
a = 1 b = -3 c = - 28
Δ = b² -4.a.c
Δ = (-3)² - 4.(1).(- 28)
Δ = 9 - 112
Δ = 121
x = - b ± √Δ
2.a
x = - (-3) ± √121
2.1
x = +3 ± 11
2
x'= 3 + 11 = 14 = 7
2 2
x"= 3 - 11 = - 8 = - 4
2 2
S[-4 , 7]
d) x² +12x+ 36=0
a = 1 b = + 12 c = +36
Δ = b² -4.a.c
Δ = (12)² - 4.(1).(+36)
Δ =144 - 144
Δ = 0
x = - b ± √Δ
2.a
x = - (+12) ± √0
2.1
x = -12 ± 0
2
x'= -12 + 0 = -12 = - 6
2 2
x"= -12 - 0 = -12 = - 6
2 2
S[- 6]
e) 9x² +2x +1=0
a = 9 b = +2 c = +1
Δ = b² -4.a.c
Δ = (-2)² - 4.(9).(+1)
Δ = 4 - 36
Δ = - 32
Acho que deu pra entender
Espero ter ajudado!!!
Explicação passo-a-passo: