The cost of a carpet of area ${A}$ $\text{m}^{{2}}$ is $C$. It is known that ${C}$ is a sum of two parts, one part varies as ${A}$ and the other part varies as the square of ${A}$. When ${A}={7}$, ${C}={1008}$; when ${A}={14}$, ${C}={2800}$.

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