Find the mean of the first four test scores first.
(Add all numbers in set and divide by how many numbers there are)
81 + 87 + 71 + 89 = 328 / 4 = 82
Then, find the mean with the 85 added as the fifth term.
81 + 87 + 71 + 89 + 85 = 413 / 5 = 82.6
The impact that the 85 had on the mean test score was that the mean/average increased by 0.6.
Answer:
x = 7, x = -10
Step-by-step explanation:

Use the quadratic formula.

Solve.
x = 7, x = -10
You can also factor if you want - that is a faster method.
Answer:
1/3
Step-by-step explanation:
rise over run. Find two places that land on a line I picked (0,0) and (3,1) then count up one from the first point and over 3 for the second.