Question

A) 2x elevado a 2-10x-12=0

B) 8x elevado a 2 - 7=0

C) 1 + 12x=9x elevado a 2

Answer 1

Resposta:

a)2x² - 10x - 12 = 0

x = -(-10)+-√(-10)²-4(2)(-12)/2(2)

x = 10 +- √100 + 96 / 4

x = 10 +- √196 / 4

x = 10 +- 14 / 4

x'= 10 + 14 / 4 = 24/4 = 6

x'' = 10-14/4 =-4/4 = -1

s = {6, -1}

b)

8x² - 7 = 0

x = -(0)+-√0 - 4(8)(-7)/ 2(8)

x =+- √224 / 16

x = +-√2²·2²·2·7/16

x = +-2·2√2·7 / 16

x = +-4√14 / 16

x = +-√14 / 4

s = { +√14/4 , -√14/4 }

c)

1 + 12x = 9x²

9x² - 12x - 1 = 0

x = -(-12)+-√(-12)² - 4(9)(-1) / 2(9)

x = 12 +- √144 + 36 / 18

x = 12 +- √180 / 18

x = 2+-√180

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