Which of the following is a possible value of if given two different numbers on a number line, the number to the right is greater than the number to the left, and the positions of and are marked on a number line?
Solution
From the number line shown, we see that .
If , then successive powers of are increasing (that is, ).
Since this is not the case, then it is not true that .
If or , then successive powers of are equal. This is not the case either.
If , then successive powers of are decreasing (that is, ). This is not the case either.
Therefore, it must be the case that .
If , we would have . This is because when , then is negative and we have which gives . This is not the case here either.
Therefore, it must be the case that .
From the given possibilities, this means that is the only possible value of .
We can check that if , then and , and so we have . We can also check by substitution that none of the other possible answers gives the correct ordering of and .