SAT Subject Test Mathematics Level 2

Now,    the question    stem    says    that    y   >    0 .    Since

is  negative,   so   is negative.   So  the value   of  y   is   .  Using   the calculator,

. Thus, y ≈ 6.14.

37 . A

Set  .  To  find    the inverse,    switch  the values  of  x   and y and   then    solve   for y:

This    is  equivalent  to

8(7x)   =   y

Therefore,  f−1(x)  =   8(7x).

38 . C
Using the defining equation with n = 1, you have

Thus,   

Using   the defining    equation     with   n   =   2,  you have

Thus,   .