Explicație pas cu pas:
a)
[tex]{2}^{3} \cdot {5}^{2} - {2}^{2} \cdot 5 = {2}^{2} \cdot 5 \cdot (2 \cdot 5 - 1) = {2}^{2} \cdot 5 \cdot (10 - 1) = {2}^{2} \cdot 5 \cdot 9 \ \ \bf \vdots \ \ 9[/tex]
b)
[tex]{2}^{4} \cdot {3}^{2} \cdot {5}^{3} + {5}^{5} = {5}^{3} \cdot (16 \cdot 9 + 25) = {5}^{3} \cdot (144 + 25) = {5}^{3} \cdot 169 = {5}^{3} \cdot {13}^{2} \ \ \bf \vdots \ \ 13[/tex]
q.e.d.
