Which of the following points does not lie on the line whose equation is x+ y = 7?
(-10, 17)
(13/3, 8/3)
(-1, -6)

The answer is (-1, -6)

Let's go through all choices:
1. (x, y) = (-10, 17)
x + y = 7
-10 + 17 = 7
17 - 10 = 7
7 = 7
So, these points lie on the line.

2. (x, y) = (13/3, 8/3)
x + y = 7
13/3 + 8/3 = 7
(13 + 8)/3 = 7
21/3 = 7
7 = 7
So, these points lie on the line, too.

3. (x, y) = (-1, -6)
x + y = 7
-1 + (-6) = 7
-1 - 6 = 7
-7 ≠ 7
So, these points DO NOT lie on the line.

Horizontal change or the change of x