turkey-yks 2016 Q10

turkey-yks · Other · lys1-math Modulus function Algebraic identities and properties of modulus
Real numbers $x$ and $y$ satisfy the equality
$$\| x | + | y | | = | x + y |$$
Accordingly, which of the following inequalities is always true?
A) $x \cdot y \geq 0$
B) $x \cdot y \leq 0$
C) $x + y \geq 0$
D) $x + y \leq 0$
E) $x - y \leq 0$
Real numbers $x$ and $y$ satisfy the equality

$$\| x | + | y | | = | x + y |$$

Accordingly, which of the following inequalities is always true?\\
A) $x \cdot y \geq 0$\\
B) $x \cdot y \leq 0$\\
C) $x + y \geq 0$\\
D) $x + y \leq 0$\\
E) $x - y \leq 0$