To determine the missing step in the proof that shows the equivalence of \(12a + 10 + a\) and \(10 + a + 12a\) using the Commutative Property, let's first rewrite the original expression:
- Start with \(12a + 10 + a\).
Using the Commutative Property, we can change the order of addition. The missing step should reflect an arrangement where we can simplify the left-hand side:
The correct missing step should be:
12a + 10 + a = 10 + 12a + a
So the entire proof would look like this:
- Step 1: \(12a + 10 + a = 10 + 12a + a\) (using the Commutative Property)
- Step 2: \(10 + 13a = 10 + 13a\)
- Step 3: The expressions are equivalent because they both equal the same value.
Thus, the correct response is:
10 + 12a + a = 10 + 13a.