The range is the output value or the y value.
You would work backwards to find the domain.
f(x) = 4x - 1 f(x) = 4x - 1
3 = 4x - 1 7 = 4x - 1
add 1 to both sides add 1 to both sides
4 = 4x 8 = 4x
divide both sides by 4 divide both sides by 4
x = 1 x = 2
f(x) = 4x - 1 f(x) = 4x - 1
11 = 4x - 1 15 = 4x - 1
add 1 to both sides add 1 to both sides
12 = 4x 16 = 4x
divide both sides by 4 divide both sides by 4
x = 3 x = 4
Domain { 1, 2, 3, 4}