Question

determinati valoarea numarului natural x, stiind ca 9^x+2 +9^x+1 +9^x =91·3^28

Answer 1

$9^{x+2}$+$9^{x+1}$+$9^{x}$=91·3²⁸
$9^{x}$·(9²+9¹+9°)=91·3²⁸
$9^{x}$·(81+9+1)=91·3²⁸
$9^{x}$·91=91·3²⁸
$9^{x}$=(3²)¹⁴
$9^{x}$=9¹⁴
x=14