1. а) а²+(3а-b)² = a²+ (9a²-2×3a×b+b²) = a²+(9a²-6ab+b²) = a²+9a²-6ab+b² = 10a²-6ab+b²
б) 9b² - (a-3b)²=9b² - (a²-2×a×3b+9b²)= 9b²-(a²-6ab+9b²)= 9b²-a²+6ab-9b²= -a²+6ab
в) (5a+7b)² - 70ab = (25a²+2×5a×7b+49b²)-70ab= 25a²+70ab+49b²-70ab= 25a²+49b²
г) (8a-b)²-64a²= (64a²-2×8a×b+b²)-64a²= 64a²-16ab+b²-64a²= -16ab+b²
3. а) 2(a-b)² = 2(a²-2ab+b²) = 2a²-4ab+2b²
б) a(1+2a)² = a(1+2×1×2a+4a²)= a(1+4a+4a²)=a+4a²+4a³
в) -6(2x-y)² = -6(4x²-2×2x×y+y²)= -6(4x²-4xy+y²)= -24x²+24xy-6y²
г) -y(3x-y)²= -y(9x²-2×3x×y+y²)= -y(9x²-6xy+y²)= -9yx²+6xy²-y³