<span>d. Δf(x0) = f(x0 + Δx) − f(x0)
============================</span>
F(x) = 3x⁴ - 4x³ - 12x² + 3
f '(x) = 3(x⁴)' - 4(x³)' - 12(x²)' + 3' = 12x³ - 12x² - 24x
f '(x) < 0
12x³ - 12x² - 24x < 0
x³ - x² - 2x < 0
x(x² - x - 2) < 0
x(x - 2)(x + 1) < 0
- + - +
____________₀__________₀__________₀____________
- 1 0 2
x ∈ (- ∞ ; - 1) ∪ (0 ; 2)
<span>(2.5у-4)(6у+1.8)=0</span>
13-C
8-D
7-D
11 - D (не уверена )