Write the expression as shown on the Expression Mats. Then simplify by making zeros and combining like terms.  

1. 

   Hint (a):

   Remember that shaded tiles are positive and white tiles are negative.

   Answer (a):

   $x-2x+2-3=-x-1$

2. 

   Answer (b):

   $x+2x+x^2-1+1=x+x^2$