The following special products come from multiplying out the brackets. You'll need these often, so it's worth knowing them well.a(x + y) = ax + ay (Distibutive Law)(x + y)(x − y) = x2 − y2 (Difference of 2 squares)(x + y)2 = x2 + 2xy + y2 (Square of a sum)(x − y)2 = x2 − 2xy + y2 (Square of a difference)
