### Home > CCA > Chapter A > Lesson A.1.6 > Problem A-61

The circled tiles can be removed, since they make zero pairs. What is an expression for the remaining tiles?

2*x* − 1

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On this mat, both *x*-tiles in the (+) region can be removed, since they make a zero pair. Next, flip the −1 unit tile in the (−) region to the (+) region, and then simplify.

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Unlike in parts (a) and (b), this problem has no zero pairs. However, here is an un-simplified expression to get you started.*x*^{2} + (−1) + (−1) − (*y* + 1 + 1)

Can you simplify that expression?

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