Write  the expression shown on each of the Expression Mats below. Then simplify them by making zeros and combining like terms.  

1. 

   Hint (a):

   Notice that a grey tile and a white tile of the same value cancel each other out and make a zero. Circle around the positive x and the negative x tiles, with the tiles crossed out, labeled 0. A second circle around the positive unit and one of the negative unit tiles‌, with the tiles crossed out, labeled 0.

   More Help (a):

   Now write an expression for the values that remain. A circle is added around the remaining 2 unit tiles.

   

   

   Answer (a):

   $−2$

2. 

   Hint (b):

   See part (a).

   Answer (b):

   $2x^2+3x-1$