What is the final expansion in the model of a square with side \((2x-5)\)?

Correct answer: \(4x^2-20x+25\)

Direct answer: A is correct. The area of a square is the square of its side, so the expression is \((2x-5)^2\). Use \((a-b)^2=a^2-2ab+b^2\), with \(a=2x\) and \(b=5\). Then \(a^2=(2x)^2=4x^2\), \(-2ab=-2(2x)(5)=-20x\), and \(b^2=25\). Hence the expansion is \(4x^2-20x+25\). B incorrectly uses \(-10x\), as though the factor 2 in \(2x\) were missed. C squares \(2x\) incorrectly. D has the wrong sign; the middle term is negative because the binomial contains subtraction. Options A, B, and C have the same general term pattern but incorrect calculations in the latter two, while D has a sign error.