Find the error in the calculations below, if there is one:
Line (1): 4x³ + 2x² − 6x +3
Line (2): = 2x²(2x + 1) − 3(2x + 1)
Line (3): = 2x²(2x + 1) + ( − 3)(2x + 1)
Line (4): = (2x² − 3)(2x + 1)