Question

Determine o valor de x, sabendo que a//b//c
X+3 6
------ = ------
5 x+2

a) x=3
b) x=4
c) x=5
d) x=6

Answer 1

Multiplicação dos meios e extremos.

$\frac{x+3}{5}=\frac{6}{x+2}\\\\(x+3)(x+2)=6\cdot5\\x^2+2x+3x+6=30\\x^2+2x+3x+6-30=0\\x^2+5x-24=0$

Fórmula de Bháskara.

Coeficientes: a = 1, b = 5 e c = -24.

$\Delta=b^2-4ac\\\Delta=5^2-4\cdot1\cdot(-24)\\\Delta=25+96\\\Delta=121$

$x=\frac{-b+-\Sartre{\Delta}}{2a}\\\\x=\frac{-5+-\sqrt{121}}{2\cdot1}\\\\x=\frac{-5+-11}{2}\\\\x_1=\frac{-5+11}{2}=\frac{6}{2}=3\\\\x_2=\frac{-5-11}{2}=\frac{-16}{2}=-8$


Alternativa (a) x = 3


Espero ter ajudado.
Bons estudos! :)