Answer:
His score decreased by 9 percent this time.
Step-by-step explanation:
From his first history exam he had a score of 90 percent. The difference between his first score and present score is given by
90 - 81 = 9
Answer:
k=1
Step-by-step explanation:

Subtract 8 from both sides

Divide

Simplify

Answer:
The midpoint is (10, 4)
Step-by-step explanation:
To find the midpoint, you add the x value from the first coordinate and the x value from the second coordinate, then divide by two to get the x coordinate of the midpoint. You do the the same exact thing with the two y values to find the y coordinate of the midpoint.
2 + 18 = 20
20 / 2 = 10
1 + 7 = 8
8 / 2 = 4
(10, 4)
Hope this helps!