Question

me ajudem, com calculo

Answer 1

2.

a)
x² - 7x + 10 = 0
a = 1; b = - 7; c = 10 (completa)

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b)
x² - 16 = 0
a = 1; b = 0; c = - 16 (incompleta)

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c)

- 2x² + x - 5 = 0
a = - 2; b = 1; c = - 5 (completa)


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d)

x² + 0x + 0 = 0
a = 1; b = 0; c = 0 (incompleta)


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e)
4x² - 4x + 1 = 0
a = 4; b = - 4; c = 1 (completa)

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f)

- x² - 7x = 0

a = - 1; b = - 7; c = 0 (incompleta)

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5.

a)
4x² - 36 = 0
4x² = 36
x² = 36/4
x² = 9
x = √9
x = + 3 e x = - 3

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b)
7x² - 21 = 0
7x² = 21
x² = 21/7
x² = 3
x = √3

x = + √3 e x = - √3

c)
x² + 9 = 0
x² = - 9
x = √ - 9 (não há solução para os Números Reais)
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d)
x² - 49 = 0
x² = 49
x = √49
x = + 7 e x = - 7

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e)
5x² - 20 = 0
5x² = 20
x² = 20/5
x² = 4
x = √4
x = + 2 e x = - 2
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f)
x² - 64 = 0
x² = 64
x = √64
x = + 8 e x = - 8
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g)
- 7x² + 28 = 0
28 = 7x²
7x² = 28
x² = 28/7
x² = 4
x = √4
x = + 2 e x = - 2
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h)
9x² - 4 = 0
9x² = 4
x² =  4/9
x = √4/9
x = + 2/3 e  x = - 2/3
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i)
(x - 6).(x + 6) = 64
x² - 36 = 64
x² = 64 + 36
x² = 100
x = √100
x = - 10 e x = 10

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j)

(x - 3).(x + 4) + 8 = x
x² + 4x - 3x - 12 + 8 = x
x² + x - 4 = x
x² - 4 = x - x
x² - 4 = 0
x² = 4
x = √4
x = + 2 e x = - 2

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6.

a)
x² - 10x = 0
x.(x - 10) = 0
x = 0

x - 10 = 0
x = 10

R.: x = 0 e x = 10

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b)

2y² - 7y = 0
y.(2y - 7) = 0
y = 0

2y - 7 = 0
2y = 7
y = 7/2

R.: y = 0 e y = 7/2

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c)

5x² + 10x = 0
x.(5x + 10) = 0
x = 0

5x + 10 = 0
5x = - 10
x = - 10/5
x = - 2

R.: x = 0 e x = - 2
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d)

9x² - 9x = 0
x.(9x - 9) = 0
x = 0

9x - 9 = 0
9x = 9
x = 9/9
x = 1

R.: x = 0 e x = 1

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e)

y² - y = 0
y.(y - 1) = 0
y = 0

y - 1 = 0
y = 1

R.: y = 0 e y = 1
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f)

t² + 8t = 0
t.(t + 8) = 0
t = 0

t - 8 = 0
t = 8

R.: t = 0 e t = 8

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g)
- 11x² + 11x = 0
x.(-11x + 11) = 0
x = 0

- 11x + 11 = 0
- 11x = - 11 (-1)
11x = 11
x = 11/11
x = 1

R.: x = 0 e x = 1

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h)
x.(x - 3) - 2.(x - 3) = 6
x² - 3x - 2x + 6 = 6
x² - 5x = 6 - 6
x² - 5x = 0
x.(x - 5) = 0
x = 0

x - 5 = 0
x = 5

R.: x = 0 e x = 5
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i)

3x²    + 2x =  x² +  5  x
------                      ----
  8                           6

9x² + 48x = 24x² + 20x
------------    ---------------- 
     24                 24

9x² + 48x = 24x² + 20x
9x² - 24x² + 48x - 20x =0
- 13x² + 28x = 0
x.(-13x + 28) = 0
x = 0

- 13x + 28 = 0
- 13x = - 28 (-1)
13x = 28
x = 28/13

R.: x = 0 e x = 28/13

¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨¨
8,6: 2
4,3: 2
2,3: 2
1,3: 3
-------------
1,1   = 2.2.2.3 = 8.3 = 24

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j)
  
(3x - 2)² = 4
9x² - 2.2.3x + 4 = 4
9x² - 12x = 4 - 4
9x² - 12x = 0
x.(9x - 12) = 0
x = 0

9x - 12 = 0
9x = 12
x = 12  (:3)         4
      -----         =  ----
        9  (:3)         3

R.: x = 0 e x = 4/3
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