Question

Proszę o odpowiedź do zadania nr. 6

Answer 1

A. FALSZ
(a-b)³ = (a-b)(a²+ab+b²)
(b-a)³ = (b-a)(a²+ab+b²) = -(a-b)(a²+ab+b²)
a = b => (a-b)(a²+ab+b²) = -(a-b)(a²+ab+b²)
a ≠ b => (a-b)(a²+ab+b²) ≠ -(a-b)(a²+ab+b²)
B. PRAWDA
-a³ = (-a)³
-aaa = - aaa
C.  FALSZ
(a+b)² = a²+2ab+b²
a < 0 i b > 0 => (a+b)² ≤ a²+b²
a = 1 b = -2
a²+b² = 1+4 = 5
(a+b)² = (1-2)² = 1
1 < 5