# Problem #1639

 1639 A rectangular region is bounded by the graphs of the equations $y=a, y=-b, x=-c,$ and $x=d$, where $a,b,c,$ and $d$ are all positive numbers. Which of the following represents the area of this region? $\textbf{(A)}\ ac+ad+bc+bd\qquad\textbf{(B)}\ ac-ad$ $+bc-bd\qquad\textbf{(C)}\ ac+ad$ $-bc-bd \quad\quad\qquad\textbf{(D)}\ -ac-ad$ $+bc+bd\qquad\textbf{(E)}\ ac-ad$ $-bc+bd$ This problem is copyrighted by the American Mathematics Competitions.
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