3. а) -2a * 3a²x = -6a³x
б) -3ху³ * (-2ху²) = 6х²у⁵
в) (-2а²b)³ = -8a⁶b³
г) (-x³y)⁴ = x¹²y⁴
4. а) 8ab - (4ab + 7b - 3) + 7b = 8ab - 4ab - 7b + 3 + 7b = 4ab + 3
б) (2a - 3) (3a +2) = 6a² + 4a - 9a - 6 = 6a² - 5a - 6
в) (x - 1) (x² - 2x + 2) = х³ - 3х² - 2
г) (x - 2) (x + 2) = x² - 4
д) (2a - 3b) (2a + 3b) = 4a² - 9b²
е) (x - 1) (1 + x) = x² - 1
ж) (y + 3)² = y² + 6y + 9
з) (5x - 2y)² = 25x² - 20xy +4y²
и) x (x - 3) (x + 3) = x (x² - 9) = x³ - 9x