Упростите выражение: a) 8(5y+3)² +9 (3у – 1)²; б) (2x-5)²-2(7x-1)²; a) (4y² + 3)2 + (9-4y²)² - 2 (4y² + 3) (4y²-9); б) (a²-6ab+9b²) (a²+6ab+b²)-(a²-962)²;

а) 8(5y+3)^2 + 9(3y-1)^2 = 8(25y^2 + 30y + 9) + 9(9y^2 - 6y + 1) = 200y^2 + 240y + 72 + 81y^2 - 54y + 9 = 281y^2 + 186y + 81 б) (2x-5)^2 - 2(7x-1)^2 = (4x^2 - 20x + 25) - 2(49x^2 - 14x + 1) = 4x^2 - 20x + 25 - 98x^2 + 28x - 2 = -94x^2 + 8x + 23 а) (4y^2+3)^2 + (9-4y^2)^2 - 2(4y^2+3)(4y^2-9) = (16y^4 + 24y^2 + 9) + (81 - 72y^2 + 16y^4) - 2(16y^4 - 36y^2 + 12y^2 - 27) = 32y^4 - 48y^2 + 90 - 32y^4 + 48y^2 + 54 = 144 б) (a^2-6ab+9b^2)(a^2+6ab+9b^2) - (a^2-9b^2)^2 = ((a^2+9b^2) - 6ab)((a^2+9b^2) + 6ab) - (a^2-9b^2)^2 = (a^2+9b^2)^2 - (6ab)^2 - (a^2-9b^2)^2 = a^4 + 18a^2b^2 + 81b^4 - 36a^2b^2 - (a^4 - 18a^2b^2 + 81b^4) = a^4 - 18a^2b^2 + 81b^4 - a^4 + 18a^2b^2 -81b^4 - 36a^2b^2 = -36a^2b^2