Simplify the following expression \[ -(x+5)(x+8) \]

To simplify the expression \( -(x+5)(x+8) \), we first need to expand the product within the parentheses. Using the distributive property (also known as FOIL for binomials), we calculate: \[ (x+5)(x+8) = x^2 + 8x + 5x + 40 = x^2 + 13x + 40 \] Now, we apply the negative sign from the original expression: \[ -(x^2 + 13x + 40) = -x^2 - 13x - 40 \] So the simplified expression is: \[ -x^2 - 13x - 40 \]