Question

ex 12. b,c,d va rog mult pana dimineata imi trebuie

Answer 1

Utilizam factorul comun:

b)11001+22002+33003+44004+55005=

=11011 (1+2+3+4+5)

=11011·15

=165 015

c)5+10+15+20+25+30+35=

=5 (1+2+3+4+5+6+7)

=5·7·8/2

=140

d) 6+12+18+24+30+36+42=

=6 (1+2+3+4+5+6+7)

=6·7·8/2

=168