Explanation:
For every problem, plug in the number where the variable is.
For example:
Evaluate the following expression by substituting 8 for x.
x + 9
You would take the x and turn it into 8, then you would do 8 + 9.
Answer:
Final answer is
or
.
Step-by-step explanation:
Given equation is 
Now we need to solve that equation for x.

Apply formula 

Apply formula 






or 
or 
or 
Hence final answer is
or
.