а)... = x²+5x+6x+30 = x²+11x+30.
б)... = a²+a-4a-4 = a²-3a-4.
в)... = 2y-16-y²+8y = 10y-16-y².
г)... = 2a²+a-8a-4 = 2a²-7a-4.
д)... = 6у²+4y-3y-2 = 6y²+y-2.
e)... = 20x-15x²-12+9x = 29x-15x²-12.
а)... = x²+5x+6x+30 = x²+11x+30.
б)... = a²+a-4a-4 = a²-3a-4.
в)... = 2y-16-y²+8y = 10y-16-y².
г)... = 2a²+a-8a-4 = 2a²-7a-4.
д)... = 6у²+4y-3y-2 = 6y²+y-2.
e)... = 20x-15x²-12+9x = 29x-15x²-12.