Answer:
Alright everyone, I finally figured it out after consulting with 4 different tutors and spending 6 hours on it lol, so here it goes :).
Part A:
The interval during which the difference in sales is positive = (-9,-3)
The interval during which the difference in sales is negative = (-3,10)
The interval during which the difference in sales is increasing = (4.9,10)
The interval during which the difference in sales is decreasing = (0,4.9)
Part B:
-9, -3, 10
5
Part C:
(x + 9), (x + 3), and (x - 10)
Part D:
0.05x^3 + 0.1x^2 -4.65x - 13.5
Part E:
Wow, that one was a challenge...
0.65(x+8)(x-2)(x-6) (make sure to adjust the signs of the factors based on the sliders being in (x-m) format.
Step-by-step explanation:
For those interested in understanding how to solve the problem rather than just obtaining the answer, I get that! I struggled the same way and went through 3 tutors who simply provided answers without explanations. Therefore, I’m sharing my breakdown :).
Part A
This part was somewhat self-evident. The graph showed clear points of increase and decrease while the graph's values shifted between positive and negative at specific times as described in my answers.
Part B
The y-axis displays the average sales, so recognizing this helps us see where the graph intersects at y = 0, which occurs at x values of -9, -3, and 10. Here, the number of sales aligns with the average.
Part C
According to an algebra principle, if a factor of f(x) is expressed as f(x) = (x-m), then m represents an x-intercept. Thus, we can deduce that each x-intercept we identify on the graph corresponds to a factor of the equation of the graph when substituting the intercept for m in (x-m). This gives us three factors of the equation: (x-10), (x+3), and (x+9).
Part D
To find the equation in standard form, we first need to establish the coefficient 'a' in a(x-b)(x-c)(x-d). By substituting x = 0 for the equation's y-intercept, we arrive at -13.5 = a(0+9)(0+3)(0-10). Solving within the parentheses simplifies to -13.5 = a(9)(3)(-10). After simplifying, we find that -13.5 = -270a. To isolate 'a', we divide each side by -270, yielding a = 0.05. Thus, we can replace 'a' in our factored expression, resulting in 0.05(x+9)(x+3)(x-10). Following this, we proceed with multiplication and distribution to ultimately derive the standard form: 0.05x^3 + 0.1x^2 -0.65x - 13.5. While identifying the y-intercept is critical, it’s important to note that it’s consistently the last number without an x variable. Quite the workout, haha.
Part E
Alright, this is where I encountered significant challenges. I derived the factors by interpreting the word problem, recognizing that the competitor's sales corresponded to average sales at months -8, 2, and 6. Since the x-axis represents months and leveraging the algebra formula previously used, I can ascertain the factors of this equation as (x+8), (x-2), and (x-6). The question then arises regarding 'a'. I'm still discussing this aspect with a tutor, and I apologize for the uncertainty. I'll provide an update as soon as I have clarity, so I can assist others. If you’ve read this far, you're fantastic, and this determination is a valuable trait that will lead to success :).
I hope some of this explanation clarifies things; if not, feel free to comment, and I’ll attempt to clarify further. I’m here to help because I know the feeling of being unsupported. I truly hope I can be of assistance :)).