See attached graph (from -4<=x<=2 )
The y-intercept is the multiplier to the exponential, i.e. 2.
The graph goes from (-3,1/4) to (2, 8), so the range in interval notation is [1/4,8]
If f(x)=2(3^x), then the y-intercept stays the same at 2. The graph goes from (-3, 2/27) to (2,18), and the corresponding range will be [2/27, 18].
See second graph for more information.
