Respuesta :

 x - 1        x + 1
------ = --------------
x + 3       x + 6

if x = 9
8/ 12 = 10/15

12 (10) = 8(15)
120 = 120

so 
answer is 9 (last choice)

Answer: The value of x is 9.

Explanation:

It is given that FG || BC.

If a transversal line intersect two parallel lines then the corresponding angles are same. There in triangle ACB and AGF,

[tex]\angle GFA=\angle CBA[/tex]

[tex]\angle AGF=\angle ACB[/tex]

Angle A is common is both triangles.

[tex]\frac{FA}{BA}= \frac{GA}{CA}[/tex]

[tex]\frac{x+1}{(x+1)+(x+6)}= \frac{x-1}{(x-1)+(x+3)}[/tex]

[tex]\frac{x+1}{(2x+7}= \frac{x-1}{(2x+2)}[/tex]

[tex](x+1)(2x+2)=(x-1)(2x+7)[/tex]

[tex]2x^2+4x+2=2x^2+5x-7[/tex]

[tex]4x+2=5x-7[/tex]

[tex]x=9[/tex]

Therefore, the value of x is 9.