Math, Kaplan page 92?

[Dencology]

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guys:

i don't this problemj, pg 92 #4. it seems that A and C works but the answer is A. i pick any positive and negative number within the shaded region and according to equation A and C it is true. but the ans is A, how come? This is driving me crazy! help

 

[student253]

It may help if you included the problem, either typed out or an attached picture. Good luck!