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Suppose $c$ is a constant and $x_i \in (x_1,x_2,\ldots,x_n)$, then the expression $\sum_{i=1}^{n} cx_i$ can be written as any of the choices EXCEPT:

$c \sum_{i=1}^{n} x_i$

$cx_1 + cx_2 + \ldots + cx_n$

$c \cdot (x_1 + x_2 + \ldots + x_n)$

$c \cdot n \bar{x}$

$x_i \sum_{i=1}^{n} c$