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$ \left( { x }^{ 2 }-7 \right) -\left( { x }^{ 3 }+1 \right) $ is equivalent to which of the following?

$ { x }^{ 5 }-8 $

$ { x }^{ 5 }-7{ x }^{ 3 }+{ x }^{ 2 }-7 $

$ -{ x }^{ 3 }+{ x }^{ 2 }-8 $

$ { x }^{ 3 }+{ x }^{ 2 }-6 $