Ответ:

#1.

a) (y-4)² = y² - 8y + 16

б) (7x + a)² = 49x² + 14xa + a²

в) (3x² + x)² = 9x⁴ + 6x³ + x²

г) (5c - 1)(5c + 1) = (5c)² - 1² = 25c² - 1

д) (3a + 2b)(2b - 3a) = (2b)² - (3a)² = 4b² - 9a²

e) (y² - 2a)(y² + 2a) = y⁴ - 4a²

#2.

(a - 9)² - (81 + 2a) = a² - 18a + 81 - 81 - 2a = a² - 20a ( = a(a - 20))

#3.

a) x² - 49 = x² - 7² = (x-7)(x+7)

б) 25x² - 10xy + y² = (5x - y)²

в) 4x²y² - 9a⁴ = (2xy - 3a²)(2xy - 3a²)

г) 27 - x⁶ = 3³ - x⁶ = 3³ - (x²)³ = (3 - x²)*(x⁴ + 3x² + 9)

#4.

(2-x)² - x(x + 1,5) = 4

4 - 4x + x² - x² - 1,5x -4 = 0

-6,5x = 0

x = 0

#5.

(2 + a)²(2 - a)² = (4 - a²)² = 16 - 8a² + a⁴

#6.

25a² - (a + 3)² = (5a - (a+3))(5a + (a+3)) = (5a - a - 3)(5a + a + 3) = (4a - 3)(6a + 3)