Question

Va rog frumos sa mă ajutați!​

Answer 1

Răspuns:

$a = \frac{ {3}^{21} + {3}^{20} + {3}^{19} }{39} = \frac{ {3}^{19}( {3}^{2} + {3}^{1} + 1)} {39} = \frac{ {3}^{19}(9 + 3 + 1) }{39} = \frac{ {3}^{19} \times 13 }{39} = \frac{ {3}^{19} }{3} = {3}^{19 - 1} = {3}^{18} = ({3}^{9} )^{2}$