Question

which of the following does not show the commutative property of addition?
○ $a + b = b + a$
○ $9 + x = x + 9$
○ $3x + 4y = 4y + 3x$
○ $ab = ba$

Explanation:

Step1: Define Commutative Add Property

The commutative property of addition states that for any two values $m$ and $n$, $m + n = n + m$.

Step2: Analyze each option

• Option1: $a + b = b + a$ matches the addition property.
• Option2: $9 + x = x + 9$ matches the addition property.
• Option3: $3x + 4y = 4y + 3x$ matches the addition property.
• Option4: $ab = ba$ represents the commutative property of multiplication, not addition.

Answer:

D. $ab = ba$