The system of equations are 4x+(p6)y+8=0 and 8x+(p+5)y+7=0. Find the value of \(p\) if the system of equations has a unique solution.
 
The equations have unique solution for all real numbers except \(p \neq\) ________.
 
(Note: If the answer is a whole number mention as it is. If not round off the answer and submit as a whole number.)