Step-by-step explanation:
The equation of a exponential function is

where a is the y value of the y intercept, b is the constant rate of change.
Here the y intercept is (0,4), the y value of the y intercept is 4.
So a=4
The graph passes through point (1,2) so

Plug in 1 for x, 2 for h(x)

Anything to the first power is itself so

Isolate b.

So our function is

18 is the nearest whole number
If you go from right to left, or left to right, you won't get the right answers. By using order of operations, you will get a more accurate and correct answer.
Hope this helps :)
Answer:
all your numbers are mixed up, can you fix your question?