19. Calculaţi:
a) 6x²-9x-(2x-1)(3x-2);
c)x(15x-2)-(3x + 1)(5x - 2);
b) 6x(3x-1)-(9x - 1)(2x + 1)
d) (-x + 2)(12x-1)-(4x+5)(-3x+1)
VA ROG URGENT!!!!​