Rima wrote the length of a rectangle as \(x+3\) m and its breadth as \(x-3\) m, and stated that its area is \(x^2+9\) m². Which is the correct analysis of her error?

Correct answer: The middle terms cancel, but \(3\times(-3)=-9\); therefore, the area is \(x^2-9\).

Using distribution, \((x+3)(x-3)=x^2-3x+3x-9=x^2-9\). Rima used the wrong sign for \(3\times(-3)\). Exam tip: apply \((a+b)(a-b)=a^2-b^2\) to avoid expansion errors.