The librarian was checking the thicknesses of several books and found that the average thickness of a book was 1.8 centimeters. She found this by averaging the thicknesses of five different books. Four of the thicknesses were 1.4 cm, 1.9 cm, 2.1 cm, and 2.4 cm. What was the thickness of the fifth book that she measured?

1.2 cm

Step-by-step explanation:

1.8 * 5 = 9

9 - (1.4 + 1.9 + 2.1 + 2.4) = 1.2

1.2 + 1.4 + 1.9 + 2.1 + 2.4 = 9

9/5 = 1.8

they can both be solutions depends on the equation

step-by-step explanation:

what is the equation? ?

sample answer: you can determine whether each element of the domain is paired with exactly one element of the range. for example, if given a graph, you could use the vertical line test; if a vertical line intersects the graph more than once, then the relation that the graph represents is not a function.