# problem with factorial equations! [closed]

this is my first post here

I'm studying for an exam and have problems with simplifying math problems including factorials.

Here is an example 1: $$\frac{(n-3)!}{132} =10! \implies n=\ ?$$ apparently the answer is $15$ but i dunno the way?

another example 2: $$\frac{(a-3)!}{x!} = 120 \implies \min(a+x)=\ ?$$ (answer is $8$)

## closed as off-topic by user296602, Shailesh, Namaste, Did, user223391 Dec 28 '17 at 2:36

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question is missing context or other details: Please improve the question by providing additional context, which ideally includes your thoughts on the problem and any attempts you have made to solve it. This information helps others identify where you have difficulties and helps them write answers appropriate to your experience level." – Community, Shailesh, Namaste, Did, Community
If this question can be reworded to fit the rules in the help center, please edit the question.

• Welcome to MSE. Try using mathjax to make your question more presentable. – Mohammad Zuhair Khan Dec 27 '17 at 16:51
• hi. thnax for your welcome and also i don't know what mathjax is and how to use it really 🤔 – Danial Nikpeyman Dec 27 '17 at 22:05

Note that $132=11\times12$. So\begin{align}\frac{(n-3)!}{132}=10!&\iff(n-3)!=12\times11\times10!=12!\\&\iff n-3=12\\&\iff n=15.\end{align}Can you do the other one?