Squaring the binomial ax+b:
[tex]\begin{gathered} (ax+b)(ax+b)=(ax)\placeholder{⬚}^2+(ax)(b)+(ax)(b)+(b)\placeholder{⬚}^2 \\ (ax+b)(ax+b)=(ax)\placeholder{⬚}^2+2(ax)(b)+(b)\placeholder{⬚}^2 \end{gathered}[/tex]
As you can see above to square the given polynomial using the method A you get at the end the formula given in method B.
Then, both methods are correct
