The answer, is 2 1/9. subtract 1 7/7 from 3 1/2, and you'll get 2 1/2
(hope this helps)
Commutative Property
The sum of two or more real numbers is always the same regardless of the order in which they are added. In other words, real numbers can be added in any order because the sum remains the same.
M = 1 -1 /dx = 0
y = b
y = 1
the line is horizontal ( has one value for y for any given x)