Question

give the domain and range y=3x-2

Answer 1

domain[x] = (-infinity, +infinity)
range[x] = (-infinity, +infinity)

Answer 2

The domain is the pool of values you are allowed to take for x. The range is where you will find the output having put in a value of x into the equation.
This is a linear equation and hence it will have an infinite number of x and y coordinate points.
Therefore the domain (x values) -infinity<= x <= infinity
The range (y values) -infinity<= y <= infinity