The domain of the function y=2x+4 is (3, infinity) what is the range

It's a linear function.

y = 2x + 4 - it's a slope-intercept form

slope m = 2

y-intercept = 4

The slope m = 2 > 0, thereofre the function is increasing (going to infinity).

Calculate the value of function for x = 3:

y = 2 (3) + 4 = 6 + 4 = 10.

Therefore we have answer:

Range is (10, ∞).