(2x-1)la a 3=(2x-1)la patrat*(2x-1)=(4xpatrat-4x+1)*(2x-1)=8xla a 3-4xpatrat-8x+4x+2x-1=8xla a 3-4xpatrat-2x-1.asta i rezultatu final..sau mai poti sa faci cu formula (a-b)la a 3=ala a 3-3apatrat*b+3a*bpatrat-bla a 3...asta i formula cu care poti calcula (2x-1)la a 3