Question

Sa se rezolve ecuatia

5 la x-1 +5 la x-2 +5 la x-3=775

Answer 1

Răspuns:

Explicație pas cu pas:

$5^{x-1} + 5^{x-2} + 5^{x-3}$ = 775

$5^{x-3}$ ($5^{2}$ + 5 + 1) = 775

$5^{x-3}$ * 31 = 775

$5^{x-3$ = 775/31

$5^{x-3}$ = 25

$5^{x-3}$ = $5^{2}$

x - 3 = 2

x = 2+3

x = 5

Answer 2

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