To express the two algebraic expressions represented by the models as equivalent, we analyze the contents of each expression.
For Expression 1:
- There are 2 tall rectangular tiles labeled \( k \) contributing \( 2k \).
- There are 3 stacked square tiles labeled \( +1 \), contributing \( +3 \).
- There is 1 square tile labeled \( -1 \), contributing \( -1 \).
So, Expression 1 can be summed up as: \[ 2k + 3 + (-1) = 2k + 2 \]
For Expression 2:
- There are 2 tall rectangular tiles labeled \( k \), contributing \( 2k \).
- There are 2 stacked square tiles labeled \( +1 \), contributing \( +2 \).
So, Expression 2 can be summed up as: \[ 2k + 2 \]
Now, we can see that both expressions equal \( 2k + 2 \).
Thus, to make the algebraic expressions represented by the models equivalent:
Expression 1: \( 2k + 2 \) Expression 2: \( 2k + 2 \)
The answer is essentially the number that completes the expressions equivalently, which is 2 for the second expression.