Question 631997
x = 7 - y

When we put 
y=0,1,2,3,4,5,6,7 
we get 
x=7,6,5,4,3,2,1,0 

Graph of the above table:
{{{drawing(500,500, -10, 10, -10, 10, grid(1)
graph( 500, 500,  -10, 10, -10, 10,-x+7))}}}