Expand and simplify (x-3)(2x+4y)^2

The first step is to expand the (2x+4y)^2 bracket. Start by writing out (2x+4y)(2x+4y) and multiply out. A simple way to do this is by using the 'foil' method - multiply the 'first' terms in each bracket, followed by the 'outside' terms, the 'inside' terms and finally the 'last' terms. This gives 4x^2+8xy+8xy+16y^2. This can be simplified by collecting like terms. There are two 'xy' terms in the equation, which can be combined, giving 4x^2+16xy+16y^2. The second step is to multiply this equation by (x-3). The best way to do this is to multiply all terms by x, followed by multiplying all terms by -3. This gives 4x^3+16x^2y+16xy^2-12x^2-48xy-48y^2.