Question

( -x - 3).(3.x - 7) = 0

Answer 1

Explicação passo-a-passo:

(-x -3).(3x -7) = 0

-3x² + 7x -9x + 21 = 0

-3x² -2x + 21 = 0 .(-1)

3x² + 2x - 21 = 0

DELTA = b² - 4.a.c

DELTA = 2² - 4.3.-21

DELTA = 4 + 252

DELTA = 256

x = -b +- √DELTA

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2a

x = -2 +- √256

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2.3

x = -2 +- 16

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6

x¹ = -2 + 16 = 14

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6 6

x² = -2 - 16 = -18 = -3

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6 6