how to work beginning algebra

Algebra
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how do you work this problem

-2(x +6)+3(2x-5)=3(x-4)+10

Sep 3rd, 2015

Thank you for the opportunity to help you with your question!

To solve this problem, you first need to distribute the outer numbers to the inner numbers of the parentheses.  A general formula for this principle would look like this: a(b+c)=a*b+a*c.  Be careful with the positives and negatives though.  Another general formula: a(b-c)=a*b-a*c.  Now when 'a' is negative:  -a(b+c)=-a*b-a*c

-2(x+6)+3(2x-5)=3(x-4)+10      Distribute terms.

-2x-12+6x-15=3x-12+10           Now combine 'like' terms.

4x-27=3x-2                                Get the 'x' terms on one side to solve for x.

x=25




Please let me know if you need any clarification. I'm always happy to answer your questions.
Sep 3rd, 2015

need clarification I need to know when to + - * these number and the answer in the back of the book says -9 how did they get that?

Sep 3rd, 2015

Hey!  Do you mind double-checking to make sure you wrote the equation correctly?  I did the problem again and still got x=25.

Sep 3rd, 2015

As far as clarification, when a number is outside of a parentheses, you will be multiplying it to the inner numbers of the parentheses.  For example, you can see the first step in the given equation:

-2(x+6) = -2*x + -2*6

             = -2x - 12

Sep 3rd, 2015

-2x-12+6x-15=3x-12+10

Once you get to this point of the problem, it might be easiest to group the terms with 'x' and group the terms without 'x' to see things a little clearer:

(-2x+6x) + (-12-15) = 3x + (-12+10)

4x - 27 = 3x - 2

Sep 3rd, 2015

4x - 27 = 3x - 2

From here, you add 3x to the opposite side of the equation, and add 27 to the right side:

4x - 3x = -2 + 27

x = 25

Please let me know what steps you are getting stuck on if you still need more clarification :)

Sep 3rd, 2015

ok checking the problem -2(x+6)+3(2x-5)=3(x-4)+10

Sep 3rd, 2015

-2x-12+6x-15=3x-12+10

4x-27=3x-2

x=25

Honestly, I have no idea where your book is getting x=9.  The answer is definitely x=25.

Sep 3rd, 2015

Besides the answer, were you able to follow the steps that I wrote out?

Sep 3rd, 2015

yes but have one question you have (-2x+6x) + (-12-15) how did you get the 15 I am sorry I sound so dumb but I'm really have trouble with understanding this appreciate all the help you can give me 

Sep 3rd, 2015

No worries!  I'll try clarify it a little more :).  The 15 is from the left hand side of the equation:

3(2x-5)    Multiply to distribute the 3 to both terms.

3*2x + 3*-5

6x - 15


Sep 3rd, 2015

have another question this might help me when you have a - number and a + number what operation do you do? adding or subtraction

Sep 4th, 2015

It depends on how you look at it.  You can look at it as your are subtracting one number from another, or you can see it as adding a negative number, which would be the same exact thing.

5+(-2)=3

5-2=3

If you have the negative number first, it's the same thing, since you can interchange the numbers for addition:

(-2)+5=3



Sep 4th, 2015

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