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Groups and FieldsChallengeGroups and the Group Axioms

Groups and the Group Axioms · Challenge problem

In the group U(24)={1,5,7,11,13,17,19,23}U(24)=\{1,5,7,11,13,17,19,23\} under multiplication mod 2424, solve the equation 7∗x∗7=57*x*7=5 for xx. (Here the group operation is multiplication mod 2424.)