Answer:
a. f(n)=3(to the power of n)+1
n is the number of days, day one being when the student sent it to 3 others
the plus one is the one student
1. The slope intercept form is:

Where
is the slope of the line and
is the intercept with the y-axis.
2. To calculate the slope, you can use the following formula:

Where:

3. So:

4. Now you must find
. Substitute any of the given points into the equation and solve for
:

5. Therefore, the answer is the last option:
Answer:
x= 8
Step-by-step explanation:
(17x + 14)+(4x - 2) = 180
21x + 12 = 180 : add like terms
21x = 168 : subtract 12 from both sides
x = 8 : divide by 21 to get x alone