The x-axis serves as a horizontal asymptote for all exponential functions. Exponential functions are of the form f(x) = ax . The domain consists of all real numbers. However, the range only consists of all numbers greater than zero. This is because no matter how large x gets, the graph will shoot upwards towards infinity. If x becomes a negative, we know that we will get f(x) = 1/a2 . The larger the negative number, the closer the function approaches zero. So, for exponential functions we will always have that restriction that the range will only include positive numbers. I hope this answers your question. I believe the statement is true.
You move the decimal to the left until there is one remaining number before the decimal. Your exponent to the ten is how many decimal places you moved.