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.

the least common denominatore of 7 and 2 is 9

step-by-step explanation:

7+2=9

  or  

step-by-step explanation:

if the four friends split the cost, p, of the pizza evenly, then each friend pays one-fourth of the cost of the pizza.

the expression is   or