Answer:
"B". Domain is all real numbers, and the Range is all positive real numbers
Explanation:
It is important to recognize that this function is an exponential function, either by the graph (observe a horizontal asymptote on the x-axis, and increasing exponentially), or more importantly by the equation which is in exponential form
where "a" is a non-zero real number, and "b" is a positive real number not equal to 1.
Observe that for the given function, a=4 (a real number not equal to zero), and b=2 (a positive real number that is not 1).
The domain for all exponential functions is all real numbers, so this function's domain is all real numbers.
The Range for exponential functions depends on "a", where if "a" is a positive number the Range is positive numbers only, and if "a" is a negative number, the Range is negative numbers only.
Since "a" is positive, the Range is positive numbers only.
Writing the Domain in "set-builder notation" (since all of the choices are given using that notation), the Domain is "all real numbers" put into curly brackets, so {all real numbers}.
Writing the Range in "set-builder notation", recall that the Range is the outputs of the function, so the Range is "y values such that y is greater than zero". There is some shorthand used, where the phrase "such that" is symbolized using a short vertical line (common in set-builder notation), and the phrase "y is greater than zero" is shortened using inequality symbols "y>0". So, the Range is written as y .
Further, the "Domain" and "Range" are abbreviated with "D" and "R" respectively.
Therefore, the final answer would be D = {all real numbers}; R = y , which is answer "B"