# Variable Summations

Algebra Level pending

Find the value for the above summation:

Providing that 'x' is an integer and the summation

$\sum _{ x }^{ n }{ f\left( x \right) }$

implies the sum of all the values created by the function (inputting the variables) for integers between 'x' and a value 'n' including 'x' and 'n' .

E.G.:

$\sum _{ 1 }^{ 3 }{ 2x+1 }$ =[2(1)+1]+[2(2)+1]+[2(3)+1]=3+5+7=15

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