Ordering and Sign Analysis from Inequality Constraints
The question gives constraints on variables (e.g., absolute values, products, orderings) and asks to determine the correct ordering, sign, or specific values of the variables.
For real numbers $a, b$ and $c$, $$a > a \cdot b > 2 \cdot a > a \cdot c$$ is known to hold. Accordingly, which of the following could be the representation of the numbers $\mathbf{a, b}$ and $\mathbf{c}$ on the number line? A) [number line A] B) [number line B] C) [number line C] D) [number line D] E) [number line E]
Let $x$ and $y$ be real numbers, $$x^{2} \cdot y^{2} < x \cdot y < x^{2} \cdot y$$ Given this inequality. Accordingly, I. $x < 1$ II. $y < 1$ III. $x \cdot y < 1$ Which of these statements are true? A) Only I B) Only II C) I and III D) II and III E) I, II and III
Let $x$ be a real number different from $-1, 0$ and $1$. $$\left\{ x^{3}, x^{2}, x, -x, -\frac{1}{x} \right\}$$ When the elements of the set are arranged from smallest to largest, which element never occupies the exact middle position? A) $x^{3}$ B) $x^{2}$ C) $x$ D) $-x$ E) $-\frac{1}{x}$