Explicație pas cu pas:
a)
[tex] \bf 9^{7}= \big(3^{2} \big)^{7} = \green{ \underline{\big(3^{7} \big)^{2} \implies \: patrat \: perfect}}[/tex]
[tex]\bf 4^{5}= \big(2^{2} \big)^{5} = \blue{ \underline{\big(2^{5} \big)^{2} \implies \: patrat \: perfect}}[/tex]
b)
Aici ai o greșeală de scriere a enunțului (7⁴ + 7⁵) · 49
[tex]\bf \big(7^{4} + 7^{5}\big) \cdot49= 7^{4} \cdot\big(7^{4 - 4} + 7^{5 - 4}\big) \cdot 7^{2} =[/tex]
[tex]\bf 7^{4} \cdot\big(7^{0} + 7^{1}\big) \cdot 7^{2} = 7^{4 + 2} \cdot\big(1 + 7\big) = [/tex]
[tex]\bf 7^{6} \cdot8= \big(7^{2} \big)^{3} \cdot 2^{3} = \red{ \underline{\big(7^{2} \cdot 2\big)^{3} \implies \: cub \: perfect}}[/tex]
