Problem 1
With limits, you are looking to see what happens when x gets closer to some value. For example, as x gets closer to x = 2 (from the left and right side), then y is getting closer and closer to y = 1/2. Therefore the limiting value is 1/2
Another example: as x gets closer to x = 4 from the right hand side, the y value gets closer to y = 4. This y value is different if you approach x = 0 from the left side (y would approach y = 1/2)
Use examples like this and you'll get the results you see in "figure 1"
For any function values, you'll look for actual points on the graph. A point does not exist if there is an open circle. There is an open circle at x = 2 for instance, so that's why f(2) = UND. On the other hand, f(0) is defined and it is equal to 4 as the point (0,4) is on the function curve.
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Problem 2
This is basically an extension of problem 1. The same idea applies. See "figure 2" (in the attached images) for the answers.
Answer: the slope intercept form for this situation is y = 0.07x + 39
Step-by-step explanation:
The cell phone package charges $39 even if 0 minutes are used during the month. This means that the package has a constant charge of $39.
Each additional minute of talk time adds $0.07. Assuming x additional minutes of talk time is made, the total cost of x additional minutes of talk time would be
0.07x + 39
Let y represent the total cost of x additional minutes, then
y = 0.07x + 39
The equation for the slope intercept form is expressed as
y = mx + c
Where
m = slope
c = intercept.
Comparing with our equation,
The slope is 0.07 and the intercept is 39
It would be 9 buddy. Negative divided by negative turns into positive. 45 divided by 5 is 9.