Question

$2 \sqrt{ x + 1} = 7$
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Answer 1

Explicação passo-a-passo:

$2\sqrt{x + 1} = 7 \\\ \sqrt{x + 1} = \frac{7}{2} \\\\ x + 1 = (\frac{7}{2})^2 \\\\ x + 1 = \frac{49}{4} \\\\ x = \frac{49}{4} - 1 \\\\ x = \frac{49 - 4}{4} \\\\ x = \frac{45}{4}\space ou\space 22,5$

Espero ter ajudado.