Question

Question was provided via image upload.

Explanation:

Step1: Simplify left side

Subtract 81 from \(81 + b^2\), we get \(b^2\) (since \(81 - 81 = 0\), so left side is \(b^2\)).

Step2: Simplify right side

Subtract 81 from 225: \(225 - 81 = 144\). So right side is 144.

Answer:

\(b^2 = 144\) (The left box is \(b^2\), the right box is \(144\))