over which interval is the graph of the parent absolute value function (f(x)=|x|) decreasing?\n(…

over which interval is the graph of the parent absolute value function (f(x)=|x|) decreasing?\n( (-infty,infty))\n( (-infty,0))\n( (-6,0))\n( (0,infty))
Answer
Answer:
B. $(-\infty, 0)$
Explanation:
Step1: Recall absolute - value function definition
$f(x)=\begin{cases}x, & x\geq0\ -x, & x < 0\end{cases}$
Step2: Analyze the slope for $x < 0$
For $x<0$, $f(x)=-x$. The slope of $y = -x$ is $- 1<0$. So the function is decreasing on the interval $(-\infty,0)$.
Step3: Analyze the slope for $x\geq0$
For $x\geq0$, $f(x)=x$. The slope of $y = x$ is $1>0$, so the function is increasing on the interval $[0,\infty)$. Thus, the graph of $y = |x|$ is decreasing on $(-\infty,0)$.