How to combine this problem

• Aug 6th 2011, 09:58 PM
queequeeg
How to combine this problem
I am doing homework on Combine Like terms. But I came to a problem that i just need to know the "how to" on this one.

-2n - (9 - 10n)

Now the answer is 8n - 9

I got at first -12n - 9

Can someone just explain the proper steps for this problem?
• Aug 6th 2011, 10:51 PM
abhishekkgp
Re: How to combine this problem
Quote:

Originally Posted by queequeeg
I am doing homework on Combine Like terms. But I came to a problem that i just need to know the "how to" on this one.

-2n - (9 - 10n)

Now the answer is 8n - 9

I got at first -12n - 9

Can someone just explain the proper steps for this problem?

$-2n-(9-10n)=-2n-(+9)-(-10n)=-2n-9+10n=(-2n+10n)-9=8n-9$
• Aug 6th 2011, 11:06 PM
benny92000
Re: How to combine this problem
Remember that two negatives equals a positive. The "-10" is negative, so when you subtract from a negative 10 you get positive 10.