Fill in the missing element to obtain a true expression:
Fill in the missing element to obtain a true expression:
To solve this problem, we'll follow these steps:
Now, let's work through each step:
Step 1: The given expression is . Observe that 49 is a perfect square, written as .
Step 2: According to the difference of squares formula, can be rewritten as , which equals .
Step 3: Plugging in our values, we know the expression matches the form , with being the missing number.
Therefore, the solution to the problem is 7, which corresponds to choice 2.
7