Question

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

Answer 1

$Dai~factor~comun~pe~x:$

$x(1+2+3+...+10)=385$

$x*\frac{10*11}{2}=385$

$x*5*11=385$

$x*5=385:11$

$x*5=35$

$x=35:5$

$\boxed{x=7}$