Terry scored 71, 80, and 86 on his first three history tests. What must terry score on the fourth test to have a mean of exactly 80

83

Step-by-step explanation:

You are trying to find the score that gives you a specific mean.  A mean is calculated by dividing the sum of the data by the amount of data.  Set up in this order, with x as the fourth score, to find the answer.

The fourth test score must be an 83.

(5x-1)^2= (5x)^2-2(5x)×1+(1)^2=25x^2-10x+1

my apex says that it is false