Respuesta :

3x + 1 = 1/3x + 9 Multiply through by 3 
9x + 3 = x + 27 Subtract x 
8x + 3 = 27 Subtract 3 
8x = 24 
x = 3 

AK = 3*3 + 1 = 10 

AB = 2*AK = 20