SAT Subject Test Mathematics Level 1

4:

12 . C

Plug    a   =   10  and b   =    3  into    the definition:

13 . C
If you add the equations as presented, the y’s drop out:

The only    answer  choice  that    works   is  (C).    To  confirm,    plug    x   =   7   back    into

one of  the original    equations   to  find    y   :

14 . D
To solve an equation with absolute value, consider the two possibilities.