If a relation contains the points (1,2) and (3,4), what is the range?

If a relation contains the points (1,2) and (3,4), what is the range?

• A. {1,2}
• B. {1,3}
• C. {3,4}
• D. {2,4}

Answer: (D)

Range is all the y-values that appear in the ordered pairs. From the points (1,2) and (3,4), the y-values are 2 and 4, so the range is {2,4}. This set lists exactly the second coordinates that show up in the relation. The other options mix x-values or include numbers that aren’t shown as y-values here. If you were asked for the domain, you’d list the x-values {1,3}.

Range is all the y-values that appear in the ordered pairs. From the points (1,2) and (3,4), the y-values are 2 and 4, so the range is {2,4}. This set lists exactly the second coordinates that show up in the relation. The other options mix x-values or include numbers that aren’t shown as y-values here. If you were asked for the domain, you’d list the x-values {1,3}.