??$解：{a}^{9}=a·{a}^{8}={a}^{2}·{a}^{7}={a}^{3}·{a}^{6}={a}^{4}·{a}^{5}$??
??$有4種寫法$??
??${a}^{9}={a}^{1}·{a}^{1}·{a}^{7}={a}^{1}·{a}^{2}·{a}^{6}={a}^{1}·{a}^{3}·{a}^{5}={a}^{1}·{a}^{4}·{a}^{4}={a}^{2}·{a}^{2}·{a}^{5}={a}^{2}·{a}^{3}·{a}^{4}={a}^{3}·{a}^{3}·{a}^{3}$??
??$有7種寫法$??
