Answer:
The value of the Rational expression when
is: 
Step-by-step explanation:
For this exercise is important to remember:
- When a negative number is raised to an even power, the result will be positive.
- The multiplication of signs:

Then, given the following Rational expression:

You need to follow these steps in order to find its value when
:
1. Substitute the given value of "x" (
) into the expression:

2. Evaluate and simplify:

Answer:
i think its 75 but im not 100 i would try to get a better answer but
Step-by-step explanation:
Answer:
D(t)=-cos(3t)
Step-by-step explanation: