Question

6+12+18+....+60=
helppp repedeee

Answer 1

6+12+18+...+60=
=6(1+2+3+..+10)
=6*10*11:2 (se simplifica 10 cu 2)
=6*5*11
=6*55
=330

Sper ca te-am ajutat!

Answer 2

[tex]6+12+18+...+60 [/tex]

aⁿ=a₁+(n-1)d
60=6+(n-1)(6)
n=10

stiind ca n=10 ⇒ a₁+aⁿ/2*n
⇒6+60/2*10 =330.

aⁿ -  ⁿ este jos nu sus.