# How do you find the domain and range of y = 3x + 8?

I found all the real $x$ and all the real $y$.
Your equation represents, graphically a straight, line of slope $3$ and passing through $x = 0 , y = 8$.
It can accept any real $x$ value and gives you, as a result, any real $y$ value; so the domain is all the real $x$ and range all the real $y$.