Question

$\frac{x + 7}{x + 5} = \frac{12}{x - 5}$
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Answer 1

Resposta:

(x+7) . (x-5) = (x-5) . 12

x² - 5x + 7x - 35 = 12x - 60

x² - 5x + 7x - 12x - 35 + 60 = 0

x² - 10x + 25 = 0 => a= 1; b= - 10; c= 25

▲= b² - 4.a.c

▲= (-10)² - 4. 1. 25

▲= 100 - 100

▲= 0

x= -b ± √▲ / 2.a

x= - (-10) ± √0 / 2.1

x= 10 / 2

x= 5

S={5}