Answer:
c. 20
General Formulas and Concepts:
Calculus
Limits
Limit Rule [Constant]:

Limit Rule [Variable Direct Substitution]:

Limit Property [Addition/Subtraction]:
![\displaystyle \lim_(x \to c) [f(x) \pm g(x)] = \lim_(x \to c) f(x) \pm \lim_(x \to c) g(x)](https://img.qammunity.org/2020/formulas/mathematics/high-school/rueapp4p7cyp6zpgjfymxh4ggg893jgv1u.png)
Limit Property [Multiplied Constant]:

Explanation:
We are given the following limit:

Rewriting this limit using limit properties, we obtain:

Evaluate the limits using various limit rules:

Simplify:

And we have our answer.
Topic: AP Calculus AB/BC (Calculus I/I + II)
Unit: Limits