To find the constant in the resulting expression when \((-7x-8)\) is added to \((5-2x)\), we first perform the addition:
\[ (-7x - 8) + (5 - 2x) \]
Now, combine like terms. For the \(x\) terms, we have:
\[ -7x - 2x = -9x \]
For the constant terms, we have:
\[ -8 + 5 = -3 \]
Putting it all together, the resulting expression is:
\[ -9x - 3 \]
The constant in this expression is \(-3\).
Thus, the correct answer is -3.