Question

Giúp tôi với :

Tìm x :

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

 

 

Answer 1

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

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

\(\Rightarrow31x+465=1240\)

\(\Rightarrow31x=775\)

\(\Rightarrow x=25\)

Answer 2

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

\(\Rightarrow\left(x+x+x+...+x\right)+\left(1+2+...+30\right)=1240\) ( 31 số x )

\(\Rightarrow31x+465=1240\)

\(\Rightarrow31x=775\)

\(\Rightarrow x=25\)

Vậy x = 25

Answer 3

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

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

31x+465=1240

31x=775

x=25

Answer 4

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

\(\Rightarrow\)(x+x+x+........+x)+(1+2+3+.........+30)=1240

\(\Rightarrow\)31x=775

\(\Rightarrow\)x=25

Answer 5

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