Răspuns :
Răspuns:
Explicație pas cu pas:
[tex]5^{x-1} + 5^{x-2} + 5^{x-3}[/tex] = 775
[tex]5^{x-3}[/tex] ([tex]5^{2}[/tex] + 5 + 1) = 775
[tex]5^{x-3}[/tex] * 31 = 775
[tex]5^{x-3[/tex] = 775/31
[tex]5^{x-3}[/tex] = 25
[tex]5^{x-3}[/tex] = [tex]5^{2}[/tex]
x - 3 = 2
x = 2+3
x = 5
Răspuns:
5^x-1 +5^x-2 +5^x-3=775
5^x(1/5+1/25+1/125)=775
5^x(25+5+1)/125=775
5^x=775×125/31
5^x=3125
5^x=5^5
x=5