Still combining like terms?

Question

3 (2b - a) - (2b - a)

I know you distrubute and all that but what about when the letter is in the number?

Show your work.
And tell me the order of how to do things

Im sorry
3 (2b - a ) - (2a - b)

Answer 1

Multiply first, then do the adding/subtracting:

3 (2b - a) - (2b - a) =

3*2b - 3*a - (2b -a) =

6b -3a - 2b + a =

{{ notice in that one above that when I have a negative in front of a parentheses it's just like a -1 times what's in the parentheses, so when I remove the parentheses it's like taking -1 times what is inside, so -(2b-a) = -2b -(-a) = -2b+a }}

Now I can combine my a's and b's:

6b - 3a - 2b + a =

4b - 2a

Hope that helped you! :-)

Answer 2

Order of Operations Rules:

Rule 1: First perform any calculations inside parentheses.
Rule 2: Evaluate any exponents.
Rule 3: Perform all multiplications and divisions, working from left to right.
Rule 4: Do all additions and subtractions, working from left to right.

A mnemoncs for this is PEMDAS ( Parenthesis, Exponents, Multiplication and Division, Addition and subtraction).

Now let's go through the problem:

3 (2b - a) - (2a - b)

1- Okay, first you distribute the 3 into the first parenthesis (x is multiplication)

3 (2b - a) = (3 x 2b - 3 x a) = 6b - 3a

2- Now you have this: (6b - 3a) - (2a - b). The second step is to distribute the second parenthesis:

- (2a - b)= -1 x 2a - -1 x b = -2a + b

(the product of two negative numbers is a positive one).

3. You have this : 6b - 3a - 2a + b, no you simply combine like terms to simplify the expression.

6b + b - 3a - 2a = 7b - 5a

Remember that you can't combine terms if they are not the same.

This website has some good info on number properties.

http://mathforum.org/dr.math/faq/faq.property.glossary.html

I hope this helps you. Good luck and keep practicing ;-)

Answer 3

First, you use the distributive property to get rid of both of the parenthasees.
So distribute the 3 to the 2b and get 6b.
Then distribute the 3 to the -a and get -3a
So the 1st half of the eqation looks like this
6b-3a
Next, you distribute the negative to the other parenthesses.
Basiclly turn whatever is in the parenthees to opposite and get
-2b and a
So the second half of your equation would look like this.
-2b+a
Now, combine the two halves
6b-3a-2b+a
So now you have gotten rid of the parenthasees look for the like terms. The like terms will consist of numeral constants with the same variable attached. So first you can combine the 6b and the -2b and get 4b.
Next, combine the -3a and the a and be -2a
Combine both of these and get 4b-2a. You can't combine anymore so that is your final answer.

Answer 4

Angela's looks good but she mixed up the variables on the end....

3(2b-a)-(2b-a) - Distribute so.. 3*2b and 3*-a

6b-3a-(2b-a) - then -1*2b and - 1*-a

6b-3a-2b+a - you get this then...

4b-2a - combine your terms

Answer 5

3(2b-a)-(2b-a)
6b-3a-(2b-a)
6a-3b-2b+a
7a-5b
I'm PRETTY SURE that's right. Tell me if I made a careless error or something, though. xD
But you get the concept, right?