efectuati produsele incerucuite ! cât de repede puteti pls !!!

(X-3)(x-6)=x^2-6x-3x+18=x^2-9x+18
(X+4)(x+5)=x^2+5x+4x+20=xg2+9x+20
(1-2x)(3x+5)=3x+5-6x^2-10x=-6x^2-7x+5
(2x+3)(5x-4)=10x^2-8x+15x-12=10x^2+7x-12