Question

( x + 1) + (x + 4) + (x + 7) + ......... + (x + 28) = 156

Answer 1

( x + 1) + (x + 4) + (x + 7) + ......... + (x + 28) = 156

=> (x+x+...+x)+(1+4+7+...+28)=156

=>10x + 145 = 156

=> 10x=156-145=11

=> x= 11/10

Answer 2

\(\left(x+1\right)+\left(x+4\right)+\left(x+7\right)+...+\left(x+28\right)=156\)

\(\Rightarrow x+1+x+4+x+7+...+x+28=156\)

\(\Rightarrow10x+1+4+7+...+28=156\)

\(\Rightarrow10x+\frac{\left(28+1\right).\left[\left(28-1\right)\div3+1\right]}{2}=156\)

\(\Rightarrow10x+145=156\)

\(\Rightarrow10x=156-145\)

\(\Rightarrow10x=11\)

\(\Rightarrow x=11\div10\)

\(\Rightarrow x=1,1\)