Question

e) 9 + 10 +1 +...+30
Repedeee,plsssss am nevoie! Dau coroana​

Answer 1

$9 + 10 + 11 + ... + 30 = \\ ( 1 + 2 + 3 + ... + 30) - (1 + 2 + ... + 8) =$

$\frac{30 \times 31}{2} - \frac{8 \times 9}{2} = \frac{930}{2} - \frac{72}{2} = 465 - 36 = 429$

Answer 2

Salut

e)9+10+11+...+30=429

30-9+1=21+1=22

22*(9+30)/2=

11*39=

=429.