# Thread: whats the right answer

1. ## whats the right answer

4x + 12 = 3(4 - X)
well 4x + 12 = 12 - 3x
4x + 12 -12 =12 - 3x -12
= 4x -12 = 12 -12 -9
= -8x -9
=8x/8 -9/8 = - 1 1/8 book says answer is 0 . not thinking right can someone help.

2. Originally Posted by Leona_Marie
4x + 12 = 3(4 - X)
well 4x + 12 = 12 - 3x
4x + 12 -12 =12 - 3x -12
= 4x -12 = 12 -12 -9
= -8x -9
=8x/8 -9/8 = - 1 1/8 book says answer is 0 . not thinking right can someone help.
The line in red is where you started to go wrong...

You have $4x+12-12=12-3x-12\implies 4x+(12-12)=-3x+(12-12)$

Note that I put some terms in parenthesis to make the next step in the process easier to see. Can you continue?

3. Originally Posted by Chris L T521
The line in red is where you started to go wrong...

You have $4x+12-12=12-3x-12\implies 4x+(12-12)=-3x+(12-12)$

Note that I put some terms in parenthesis to make the next step in the process easier to see. Can you continue?
switching 12 around doesnt make the answer 0
4x +12 -12 = -3x + 12 -12
= 4x = -3x
=4x +3x = -3x + 3x
=7x not 0 plus the only rule is that whatever you do to the left you have to do to the right. the right in this equation is -3x so -3x -12, which is 3x -12 ,would be -9

4. Originally Posted by Chris L T521
The line in red is where you started to go wrong...

You have $4x+12-12=12-3x-12\implies 4x+(12-12)=-3x+(12-12)$

Note that I put some terms in parenthesis to make the next step in the process easier to see. Can you continue?
Originally Posted by Leona_Marie
switching 12 around doesnt make the answer 0
4x +12 -12 = -3x + 12 -12
= 4x = -3x
=4x +3x = -3x + 3x
=7x not 0 plus the only rule is that whatever you do to the left you have to do to the right. the right in this equation is -3x so -3x -12, which is 3x -12 ,would be -9
Go back and look at what Chris has shown you.

$4x+12-12=12-3x-12\implies 4x+(12-12)=-3x+(12-12)$

$4x+0=-3x+0$

$4x=-3x$

$4x+3x=0$

$7x=0$

$x=0$

5. masters , please explain to me how 7x = 0 or x = 0 the only thing I would know how to do is to devide 7x/7 0/7 = 0 ? plus Ive never seen wher you can swap + -3x + 12 or visa versa is this the case or am I missing something again. in other words the question was written out12 -3x so shouldnt the number come off the right. I think I just got it please verify.

6. Originally Posted by Leona_Marie
4x + 12 = 3(4 - X)
well 4x + 12 = 12 - 3x
4x + 12 -12 =12 - 3x -12
= 4x -12 = 12 -12 -9
= -8x -9
=8x/8 -9/8 = - 1 1/8 book says answer is 0 . not thinking right can someone help.
4x+12=12-3x

4x+3x=12-12

7x=0

x=0

expand,collect, and you're done!

7. Originally Posted by Leona_Marie
masters , please explain to me how 7x = 0 or x = 0 the only thing I would know how to do is to devide 7x/7 0/7 = 0 ? plus Ive never seen wher you can swap + -3x + 12 or visa versa is this the case or am I missing something again. in other words the question was written out12 -3x so shouldnt the number come off the right. I think I just got it please verify.
yes 0/7 is what masters did.. which = 0 and you can always swap to other sides of the equation to collect like terms(as long as you change the sign)