👤

determina numarul natural x, stiind ca x+2·x+3·x+.....+10·x=385 va rog ajutati-ma!!

Răspuns :

X(1+2+3+....+10)=385
10+1=11
(10-1):1+1=9+1=10
S=(10×11):2=5×11=55
X×55=385
X=385:55
X=7