You work backwards to get (2x-1) which gets you the root 1/2 and (2x+5) which gets you the root -5/2 after this you foil what you have so (2x-1) times (2x+5). You do 2x times 2x which gives you 4x^2 2x times 5 which gives you 10x -1 times 2x which gives -2x and lastly -1 times 5 which gives you -5 now you combine like terms and get your final answer of 4x^2+8x-5
