SAT Subject Test Mathematics Level 2

The answer is (B).

This problem could also be solved by backsolving, explained on the next page. Just try the different
choices for m, and when one of them works, you have the answer. Very often the more complicated
equations, such as the one in this problem, can be solved more easily and quickly by backsolving.

UNKNOWN IN AN EXPONENT

The procedure for solving an equation when the unknown is in an exponent is a little different. What
you want to do in this situation is to express one or both sides of the equation so that the two sides
have the same base.

Look at Example 7.

Example 7

1. If   9n  =   27 n−1, then    2n  =

(A)

(B)

(C)

(D)

(E)