Упростите выражения: 1) 3a (a+2) - (a+3) ² 2) 3 (y-1) ²+6y 3) 8c+4 (1-c) ² 4) 4ab+2 (a-b) ² 5) 3 (x+y) ²-6xy

1) 3a (a+2) - (a+3) ² = 3a (a+2) - (a+3) (a+3) = 3a²+6a - (a²+6a+9) = 2a²-9

2) 3 (y-1) ²+6y = 3 (y-1) (y-1) + 6y=3 (y²-2y+1) + 6y=3y²-6y+3+6y=3y²+3=3 (y²+1)

3) 8c+4 (1-c) ² = 8c+4 (1-2c+c²) = 8c+4-8c+4c²=4 (c²+1)

4) 4ab+2 (a-b) ² = 4ab+2 (a²-2ab+b²) = 4ab+2a²-4ab+2b²=2 (a²+b²)

5) 3 (x+y) ²-6xy = 3 (x²+2xy+y²) - 6xy=3x²+6xy+3y²-6xy=3 (x²+y²)