First, you should solve for , which equals . Now, solve the integral of =, to get that. You can check this by taking the integral of what you got. Now by the Fundamental Theorem.
This should be the answer to your question, if I understood what you were asking correctly.
The given value states that all values of x will be replaced by 1. The definition of a variable in algebra is a symbol for a number we don't know yet, so x will be the variable in this equation