The amplitude of f(x) = 3sin(2x) is 3.
That means the range of the function is [-3,3]
But when you add 5 to the right side, it shifts the
graph upward 5 units. So we add 5 to both the -3
and the 3 and get -3+5=2 and 3+5=8, and the range
is [2,8]
Edwin