Question

3)Resolva as equações polinomiais do 2° grau:​

Answer 1

Vamos là.

a)

4x² - 36 = 0

x² - 9 = 0

x² = 9,

x1 = -3, x2 = 3

b)

7x² - 21 = 0

x² - 3 = 0

x² = 3

x1 = -√3 , x2 = √3

c)

x² - 121 = 0

x² = 121

x1 = -11, x2 = 11

d)

3x² - 300 = 0

x² - 100 = 0

x² = 100

x1 = -10, x2 = 10

e)

5x² - 20x = 0

x² - 4x = 0

x*(x - 4) = 0

x1 = 0, x2 = 4

f)

x² - 10x + 25 = 0

(x - 5)² = 0

x1 = x2 = 5

g)

3x² - 10x + 3 = 0

delta

d = 100 - 36 = 64

x1 = (10 + 8)/6 = 3

x2 = (10 - 8)/6 = 1/3

h)

2x² - 11x + 5 = 0

delta

d = 121 - 40 = 81

x1 = (11 + 9)/4 = 5

x2 = (11 - 9)/4 = 1/2

i)

4x² - 3x - 1 = 0

delta

d = 9 + 16 = 25

x1 = (3 + 5)/8 = 1

x2 = (3 - 5)/8 = -1/4

j)

x² - 20x + 100 = 0

(x - 10)² = 0

x1 = x2 = 10