You can put this solution on YOUR website! Ok first you must multiply the numbers in parenthesis by using foil.
5x^2+3(2x-1)-4x(2x^2-3x-1)
5x^2+6x-3-8x^3+12x^2+4x
now put all like terms together and add or subtract.
5x^2+12x^2+6x+4x-8x^3-3
17x^2+10x-8x^3-3
good luck