In the set of ordered pairs<span> {(-2, 0), (0, 6), (2, 12), (4, 18)}, the domain is the set of the first number in every</span>pair<span> (those are the x-coordinates): {-2, 0, 2, 4}. The</span>range<span> is the set of the second number of all the </span>pairs<span>(those are the y-coordinates): {0, 6, 12, 18}. There you go :)
take the group of numbers and put them from least to greatest. then, take the lowest number and subract that from the highest number.
for example, if i have the numbers 2,7,4,5 i would put them in order (least to greatest), which would be: 2,4,5,7 then, you subract 7-2, and that equals 5 :)