## Intermediate Algebra (6th Edition)

The commutative property holds that $a+b=b+a$, for real numbers a and b. In this example, we are given $(7+y)+(3+x)$. We can set (7+y) equal to $a$ and (3+x) equal to $b$. We know that $a+b=(7+y)+(3+x)$. Therefore, we know that $b+a=(3+x)+(7+y)$.