Answer:
Step 2 : The error started at this step, when the student took 2x and 3x [Instead of 3x and 3x]. This is because 3x and 3x multiply to 9x^2 and sum up to 6x;whereas 2x and 3x multiply to 6x^2 and sum up to 5x.
Correction :
[tex]1) x^2+6x+9\\2)x^2+3x+3x+9\\3)x(x+3)+3(x+3)\\4)(x+3)(x+3)[/tex]
