Question

${x}^{ - 50} + {x}^{ - 40}$
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Answer 1

${x}^{-40}({x}^{-10}+{x}^{0})$

Answer 2

${x}^{ - 50} + {x}^{ - 40} \\ \\ {x}^{ - 50 + ( - 40)} \\ \\ {x}^{ - 50 - 40} \\ \\ {x}^{ - 90}$