Answer:
1.46
Step-by-step explanation:
First find the the mean score before he made a 90.

Now add the score of 90 and calculate.

Subtract the two scores.

His mean test score increased by 1.46.
Y2-y1/x2-x1
8-[-13]/17-17
21/0
this is called undefined because its denominator is zero.
Answer:
85
Step-by-step explanation:
85+ 80 = 185
i dont think this is right tho