Simplify the given algebraic expression: $x^{2}+4 x-77$

Step 1 ：The given expression is a quadratic expression: \(x^{2}+4 x-77\).

Step 2 ：It is already in its simplest form. There are no like terms to combine or any common factors to factor out.

Step 3 ：Therefore, the simplified form of the expression is the expression itself.

Step 4 ：Final Answer: The simplified form of the given algebraic expression is \(\boxed{x^{2}+4 x-77}\).