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# Given $E(X+c)=8$ and $E(X-c)=12$ then the value of $c$ is

$\begin{array}{1 1}(1)-2&(2)4\\(3)-4&(4)2\end{array}$

$E(X+c)=8$
$E(X)+E(c)=8$
$E(X)+c=8$-------(1)
$E(X-c)=12$
$E(X)-E(c) =12$ --------(2)
$E(X)-c=12$
(1) -(2) =>$2c=-4 =c=-2$
Hence 1 is the correct answer.