Question

sabendo que
$\frac{2}{x + 5} = 4$
calcule o valor
$\frac{3}{x + 6}$

​

Answer 1

Explicação passo-a-passo:

$\sf \dfrac{2}{x+5}=4$

$\sf 4\cdot(x+5)=2$

$\sf 4x+20=2$

$\sf 4x=2-20$

$\sf 4x=-18$

$\sf x=\dfrac{-18}{4}$

$\sf x=\dfrac{-9}{2}$

Logo:

$\sf \dfrac{3}{x+6}=\dfrac{3}{\frac{-9}{2}+6}$

$\sf \dfrac{3}{x+6}=\dfrac{3}{\frac{-9+12}{2}}$

$\sf \dfrac{3}{x+6}=\dfrac{3}{\frac{3}{2}}$

$\sf \dfrac{3}{x+6}=\dfrac{3}{1}\cdot\dfrac{2}{3}$

$\sf \dfrac{3}{x+6}=\dfrac{6}{3}$

$\sf \red{\dfrac{3}{x+6}=2}$

Answer 2

Oie, Td Bom?!

• Primeiramente temos que:

2/[x + 5] = 4

(x + 5) . 2/[x + 5] = 4(x + 5)

2 = 4(x + 5)

2 = 4x + 20

- 4x = 20 - 2

- 4x = 18

x = 18/-4

x = - 18/4

x = - [18 ÷ 2]/[4 ÷ 2]

x = - 9/2

• Então agora:

= 3/[x + 6] ⇐ x = - 9/2

= 3/[- 9/2 + 6]

= 3/[{- 9 + 12}/2]

= 3/[3/2]

= 3 ÷ 3/2

= 3 . 2/3

= [3 . 2]/3

= 6/3

= 2

Att. Makaveli1996