SAT Subject Test Mathematics Level 2

Solution    3:  Backsolving

Plug    in  each    of  the answer  choices,    using   s   −   1   =   x   to  translate   from    s   to  x values,   and see

which   is  the smallest    that    works   in  the equation.

2 . D
Perform the inside functions first:

Then    perform the outside functions   on  the results:

Now you can find    the difference:

g(f(−2))    –   f(g(−2))    =   −48 –   (−432)  =   384

3 . A
The absolute value must be at least 0, so the expression must be at its minimum when it is
equal to 0.

Of  these,  only    −9  is  an  answer  choice, so  (A) is  correct.

You can also    backsolve   fairly  easily  on  this    question—plug   in  each    answer  choice, and see

which   gives   you the smallest    value   for the function.