Question

Como resolve isso? 5+C×,2=×+14?

Answer 1

Boa noite Oliveraaline

5 + C(x,2) = x + 14 

C(x,2) = x!/(x-2)!2! = x*(x - 1)*(x - 2)!/(x - 2)!2

5 + x*(x - 1)/2 = x + 14

10 + x² - x = 2x + 28

x² - 3x - 18 = 0

delta
d² = 9 + 72 = 81
d = 9

x = (3 + 9)/2 = 12/2 = 6 

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Answer 2

Boa noite Oliveraaline

5 + C(x,2) = x + 14 

C(x,2) = x!/(x-2)!2! = x*(x - 1)*(x - 2)!/(x - 2)!2

5 + x*(x - 1)/2 = x + 14

10 + x² - x = 2x + 28

x² - 3x - 18 = 0

delta
d² = 9 + 72 = 81
d = 9

x = (3 + 9)/2 = 12/2 = 6 

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