इस पर अटक गए? इसे AI से हल करें
Algebra · real student question

Graph f(x) = -|x + 5| - 4. Identify the vertex, the direction it opens, the intercepts, and the range.

Question

Graph f(x)=−∣x+5∣−4f(x)=-|x+5|-4. Identify the vertex, which way the graph opens, its intercepts, and its range.

Step-by-step solution

  1. Match the equation to vertex form. Comparing with f(x)=a∣x−h∣+kf(x)=a\left|x-h\right|+k:

    a=−1,h=−5  (since x+5=x−(−5)),k=−4a=-1,\qquad h=-5\ \ (\text{since }x+5=x-(-5)),\qquad k=-4

    so the vertex is (−5,−4)(-5,-4). Rewriting x+5x+5 as x−(−5)x-(-5) before reading hh prevents the usual sign mistake.

  2. Determine the direction and steepness from aa. Because a=−1<0a=-1<0 the graph opens downward — an upside-down V — and because ∣a∣=1|a|=1 the arms have slopes +1+1 (left of the vertex) and −1-1 (right of it), the same steepness as the parent ∣x∣|x|.

  3. Build the graph as a sequence of transformations. Starting from y=∣x∣y=|x|: shift left 55 (because x+5x+5 is zero at x=−5x=-5), reflect across the xx-axis, then shift down 44:

    ∣x∣  →  ∣x+5∣  →  −∣x+5∣  →  −∣x+5∣−4|x|\;\to\;|x+5|\;\to\;-|x+5|\;\to\;-|x+5|-4

  4. Plot a few points either side of the vertex. Using the slope ±1\pm 1 from (−5,−4)(-5,-4):

    f(−7)=−2−4=−6,f(−6)=−1−4=−5,f(−5)=−4,f(−4)=−5,f(−3)=−6f(-7)=-2-4=-6,\quad f(-6)=-1-4=-5,\quad f(-5)=-4,\quad f(-4)=-5,\quad f(-3)=-6

    The symmetry about the vertical line x=−5x=-5 is visible in these values, which is a good check that the horizontal shift was applied correctly.

  5. Read off the intercepts and range. The yy-intercept is f(0)=−∣5∣−4=−9f(0)=-|5|-4=-9, giving the point (0,−9)(0,-9). For xx-intercepts you would need −∣x+5∣−4=0-|x+5|-4=0, i.e. ∣x+5∣=−4|x+5|=-4, which is impossible since an absolute value is never negative — so there are none. The maximum output is −4-4 at the vertex, so the range is

    (−∞,−4](-\infty,-4]

Answer

Vertex (−5,−4); opens downward; y-intercept (0,−9); no x-intercepts; range (−∞,−4]\text{Vertex }(-5,-4);\ \text{opens downward};\ y\text{-intercept }(0,-9);\ \text{no }x\text{-intercepts};\ \text{range }(-\infty,-4]

Need to solve a different problem like this? Open the solver →