What is the range of f(x) = 3x + 9?

The range is the values of the output.  Since there are no limits on the input, the output can  be any value.  The range is all real values (assuming we are not in complex math)

3< x< 5

step-by-step explanation:

|x - 4| < 1

there are two solutions, one positive and one negative.   remember to flip the inequality when taking the negative solution

x-4 < 1       x-4 > -1

add 4 to each side

x-4+4 < 1+4       x-4+4 > -1+4

x< 5                 x> 3

3< x< 5