Question

tìm x 

x+1+x+2+x+3+....+x+30=`795

 

Answer 1

\(x+1+x+2+...+x+30=795\\ 30x+465=795\\ 30x=795-465\\ 30x=330\\ x=330:30\\ x=11\\ Vậyx=11\)

Answer 2

\(=>\left(x+x+x+....+x\right)+\left(1+2+3+...+30\right)=795\\ =>30x+\left[\left(30\times31\right):2\right]=795\\ =>30x+465=795\\ =>30x=795-465\\ =>30x=330\\ =>x=330:30\\ =>x=11\)

Vậy \(x=11\)