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Alexcodreanu65
a fost răspuns

5+10+15+...+40 este egal ce

Răspuns :

Miky93
[tex]5+10+15+...+40= 5(1+2+3+...+8) \\\\ 5*(\frac{1+8}{2}*8)= \\\\ = 5* 9*4= \\\\ =20*9= \\\\ =\boxed{180}[/tex]
Alexababara
180
(5+15+25+35)+(10+20+30+40)=80+100