In science class, the average score on a lab report is 78 points, with all students scoring within 2.2 points of the average. If x represents a student’s score, write an equation that represents the minimum and maximum scores.
a. |x + 2.2| = 78
b. |x − 2.2| = 78
c. |x + 78| = 2.2
d. |x − 78| = 2.2
What is an equation?