Respuesta :
distribute invisible-1 to the 2x^2+4x-12
5x^2+3-2x^2-4x+12
group like terms
5x^2-2x^2-4x+3+12
3x^2-4x+15
5x^2+3-2x^2-4x+12
group like terms
5x^2-2x^2-4x+3+12
3x^2-4x+15