Question

4) Resolva as seguintes equações: a) x² – 121 = 0 b) 5x² – 20 = 0 c) 6x² + 18x = 0

Answer 1

Resposta:

a) 11.

b) 2.

c) S = [0, -3]

a) x² - 121 = 0

x² = 0 + 121

x² = 121

x = √121

x = 11

x² - 121 = 0

11² - 121 = 0

121 - 121 = 0

0 = 0

b) 5x² - 20 = 0

5x² = 0 + 20

5x² = 20

x² = 20/5

x² = 4

x = √4

x = 2

5x² - 20 = 0

5.2² - 20 = 0

5.4 - 20 = 0

20 - 20 = 0

0 = 0

c) 6x² + 18x = 0

6x(x+3)

x = 0

6.0 (0+3) = 0

0(3)=0

0=0

x + 3 = 0

x = -3

6.-3 (-3+3)= 0

-18 (0) = 0

0 = 0