Pls. Urgent. Dau coroana

(x+y) -3 (x-2y) -5x= x+y-3x+6y-5x=x+y-3x+6y-5x= -7x+7y
(x+2) + 2(x²-3x)-3x²=x+2+2x²-6x-3x²= -x²-5x+2
(x+2)²-(x-2)²+4(2x+1)= (x²+2*2x+2²)-(x²-2*2x+2²) +8x+4 = x²+4x+4-x²+4x-4+8x+4= 16x+4
formule folosite:
(a+b)²=a²+2ab+b²
(a-b)²=a²-2ab+b²