Răspuns :
[tex] 3^{20} [/tex]* [tex] 3^{5 * 4} [/tex]=[tex] 3^{20} [/tex] * [tex] 3^{20} [/tex]=[tex] 3^{40} [/tex]
[tex] 9^{21} [/tex]=[tex] 3^{2*21} [/tex]=[tex] 3^{42} [/tex]
[tex] 3^{40} [/tex]< [tex] 3^{42} [/tex]
[tex] 9^{21} [/tex]=[tex] 3^{2*21} [/tex]=[tex] 3^{42} [/tex]
[tex] 3^{40} [/tex]< [tex] 3^{42} [/tex]
3^{20}•(3^{5})^{4}=3^{20}•3^{5•4}=3^{20}•3^{20}=3^{20+20}=3^{40}
9^{21}=(3^{2})^{21}=3^{2•21}=3^{42}
3^{40}<3^{42} => x<y
9^{21}=(3^{2})^{21}=3^{2•21}=3^{42}
3^{40}<3^{42} => x<y