Question

x + ( 1+ x ) + (2+ x ) + ( 4+ x )+ .... + ( 30 + x ) = 1240

Tìm x

Answer 1

sai đềrồi bạn ơi!!!@@

Answer 2

\(x+\left(1+x\right)+\left(2+x\right)+\left(4+x\right)+.....+\left(30+x\right)=1240\)

\(\Leftrightarrow\text{31x+(1+2+3+4+...+30)=1240 }\)

\(\text{31x+465=1240 }\)

\(\text{31x=775}\)

\(\Leftrightarrow x=25\)

Answer 3

31×x+(1+2+3+4+...+30)=1240

31×x+465=1240

31×x=1240-465

31×x=775

X=775÷31

X=25