13.11. 3) (4x - 5)(6 - 3x) - 4 < (1 - 2x)(7 + 6x)
24x - 12x² -30 + 15x - 4 < 7 + 6x - 14x - 12x²
53x < 41
x< 41/53 ⇒ x ∈ (-∞; 41/53)
4) (1.8x + 1)(5x - 1) - 2.2x > 9x² - 4
9x² - 1.8x + 5x - 1 - 2.2x > 9x² - 4
x > -3 ⇒ x ∈ (-3; ∞)
13.12. 3) (-y³ + 5y)2y - 10y²(1 + 0.2y²) = -4y⁴
(-y³ + 5y)2y - 10y²(1 + 0.2y²) = -2y⁴ + 10y² - 10y² - 2y⁴ = -4y⁴
4) (2.5a + b²)(-4a) + 2a(5a - b²) = -6ab²
(2.5a + b²)(-4a) + 2a(5a - b²) = -10a² - 4ab² + 10a² - 2ab² = -6ab²