Question

Aflați termenul necunoscut n din egalitatea 5n+10n+15n+.....+500n=75 750​

Answer 1

Răspuns:

5n(1+2+3+....+100)=75 750

5n•(100•101/2)=75 750 |:5

n•5050=15 150

n=15150:5050

n=3

Answer 2

5n+10n+15n+....+500n=75750

5n(1+2+3+...+100)=75750

5n×(100×101)/2=75750

5n×50×101=75750

505n×50=75750

25250n=75750

n=75750:25250

n=3