Chọn câu sai: (2x+3y)^2 = 4x^2 + 12xy + 9xy^2

2x + 3y2 = 4x2 + 12xy + 9y2

x - (1/2)2 = x2 – x + 1/4

x2 – 3y2 = (x + 3y)(x – 3y)

1 – 9x2 = (1 – 3x)(1 + 3x)