if and the curve passes between A(2,200) and B(2, 2000), first note that point B is higher than point A. So it means that the curve goes under B, and over A, at . Therefore :
You can then take the base-2 logarithm of each member of the inequality to extract :
(by rounding, and noting that the question says that the curve passes between the points, not through the points).
Therefore the only options left are , and
All those values of satisfy your statement. So how do we know which one is the good one ?
(!) Look at the curve : the values are negative with , and positive . This is only possible if the exponent is odd (if it is even, the result is always positive). Therefore, the only solution is ... !