Ответ:

Пошаговое объяснение:

28.

1) (a+b)(a-b)² = (a+b)(a²-2ab+b²) = a³ - 2a²b + ab² + a²b - 2ab² + b³ = a³ - a²b - ab² + b³

2) (a-b)(a+b)² = (a-b)(a²+2ab+b²) = a³ + 2a²b + ab² - a²b - 2ab² - b³ = a³ + a²b -ab² - b³

3) (1-5a)(4a+3)² = (1-5a)(16a²+24a+9) = 16a²+24a+9-80a³-120a²-45a = -80a³-104a²-21a+9

4) (2x+3y)²(2x-y) = (4x²+12xy+9y²)(2x-y) = 8x³+24x²y+18xy²-4x²y-12xy²-9y³ = 8x³+20x²y+6xy²-9y³

5) (x+3y)(x-3y)² = (x+3y)(x²-6xy+9y²) = x³-6x²y+9xy²+3x²y-18xy²+27y³ = x³-3x²y-9xy²+27y³

6) (a+2b)(a-2b)² = (a+2b)(a²-4ab+4b²) = a³-4a²b+4ab²+2a²b-8ab²+8b³ = a³-2a²b-4ab²+8b³

29. 1)

a-b = 4

(a-b)² = 16

a² - 2ab + b² = 16

a² + b² = 16 + 2ab = 16+2*5 = 26

(a²+b²)² = 676

2) x+2y = 6

(x+2y)² = 36

x² + 4y² = 36 - 4xy = 36 - 4*4 = 20

(x²+4y²)² = 400