9. Calculaţi: a) 2x + 2[4x²(3x + 2) + 2x²(x+3)]: (-14x²); b) (50x7): (-5x³)² + [6x²(x + 2)-2x²(x²-3x)]: (-2x¹); c) (x + +5)(3x - 2) - 2x(x + 7) + (x − 3)(x + 4); d) (3x + 2)(x - 5) − 4x(x − 6) − (x + 4)(x + 6); - e) (x + 6)(2x-3) + (4x+3)(x+2)-(3x+5)(x+2).
