Answer:
Any letter you want
Step-by-step explanation:
The letters used for variables don't matter. What matters is what the variables represent: their numerical value. Variables are just to help identify what needs solving. Other common variables are a, b, and c which are found frequently in trigonometry. To answer your question, there are no "next letters." You can use any letter you'd like as a variable because it holds the same numerical value. Basically, the whole alphabet is at your disposal.
Assuming the missing parenthesis is at the end the simplified answer should be k-8
Do 10 to the sixth power first then multiply that by 7 you use PEMDAS
-4 is greater than - 10 because -4 is closer to 0 than -10 is
