1. [tex] \frac{x^{2}}{y^{2}} = ( \frac{x}{y} )^{2[/tex]
[tex]x[/tex] se divide cu y daca x si y sunt cifre atunci [tex]xy[/tex] ∈{11.21.22.33.31.44.42.41.55.51.66.63.62.61.77.71.88.84.82.81.99.
93.91}
2.
3a+2b+c=72
a+b+c=43
Noi putem sa le scadem obtinem:
2a+b=29
Si le adunam obtinem:
4a+3b+2c=115
(2a+b)*(4a+3b+2c)=29*115=3335