n! = 42(n-2)!

Hi there,

My name is Damon. I am a Sask correspondence student and I have a secondary level 12 question that I can't seem to figure out.

It is as follows:

n! = 42(n-2)!

Could you please explain to me how to reach the answer. Thank you in advance for you assistance with this problem.

Yours aye,

Damon

Hi Damon,

n!=n(n-1)(n-2)! so, dividing both sides of the equation in question by (n-2)! gives n(n-1)=42 Expand and rearrange to get n²-n-42=0

Now factor and solve for n. You will find two values for n. Check to see if they are solutions to the original problem.