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