Question

qual é o valor de x6?​

Answer 1

Resposta:

b) 4

Explicação passo-a-passo:

$\frac{x}{(x + 6)} = \frac{(x + 2)}{(2x + 7)} \\ x(2x + 7) = (x + 2)(x + 6) \\ 2 {x}^{2} + 7x = {x}^{2} + 6x + 2x + 12 \\ 2 {x}^{2} - {x}^{2} + 7x - 6x - 2x - 12 = 0 \\ {x}^{2} - x - 12 = 0 \\ \\ d = {b}^{2} - 4ac \\ d = {( - 1)}^{2} - 4 \times 1 \times ( - 12) \\ d = 1 + 48 \\ d = 49 \\ \\ x = \frac{ - b \frac{ + }{ - } \sqrt{d} }{2a} \\ x = \frac{ - ( - 1) \frac{ + }{ - } \sqrt{49} }{2.1} \\ x = \frac{1 \frac{ + }{ - }7 }{2} \\ \\ {x}^{1} = \frac{1 + 7}{2} = \frac{8}{2} = 4 \\ {x}^{2} = \frac{1 - 7}{2} = \frac{ - 6}{2} = - 3$