none
Step-by-step explanation:
to solve this equation we would say that
let
x + y = 5 equation 1
x + y = 6 equation 2
from equation 2
x + y = 6 equation 2
x = 6 -y equation 3
substitute for x into equation 1
x + y = 5 equation 1
6 - y + y = 5
from here this equation cannot be solved further therefore it has no solution.