Answer:
a. Plan B; $4
b. 160 mins; Plan B
Step-by-step explanation:
a. Cost of Plan A for 80 minutes:
Find 80 on the x axis, and trave it up to to intercept the blue line (for Plan A). Check the y axis to see the value of y at this point. Thus:
f(80) = 8
This means Plan A will cost $8 for Rafael to 80 mins of long distance call per month.
Also, find the cost per month for 80 mins for Plan B. Use the same procedure as used in finding cost for plan A.
Plan B will cost $12.
Therefore, Plan B cost more.
Plan B cost $4 more than Plan A ($12 - $8 = $4)
b. Number of minutes that the two will cost the same is the number of minutes at the point where the two lines intercept = 160 minutes.
At 160 minutes, they both cost $16
The plan that will cost less if the time spent exceeds 160 minutes is Plan B.
Find the number in the thousand place
7
and look one place to the right for the rounding digit
4
. Round up if this number is greater than or equal to
5
and round down if it is less than
5
.
47000
Answer:
f(x) > 0 over the interval 
Step-by-step explanation:
If f(x) is a continuous function, and that all the critical points of behavior change are described by the given information, then we can say that the function crossed the x axis to reach a minimum value of -12 at the point x=-2.5, then as x increases it ascends to a maximum value of -3 for x = 0 (which is also its y-axis crossing) and therefore probably a local maximum.
Then the function was above the x axis (larger than zero) from 
, until it crossed the x axis (becoming then negative) at the point x = -4. So the function was positive (larger than zero) in such interval.
There is no such type of unique assertion regarding the positive or negative value of the function when one extends the interval from to -3, since between the values -4 and -3 the function adopts negative values.
Answer:
The balance of the savings account in 15 years will be $1,750.24.
