multiply out (2x-4)(x-2) and simplify.

The method I would use here is FOIL (first outer inner last). A common mistake is not multiplying out all terms, using FOIL will ensure you do this.The working I would expect to see:2x^2-4x-4x+8 (order shows use of FOIL)which simplifies to:2x^2-8x+8If this was to complicated we could move back to single brackets e.g 2(2x+4)