Expert: Scott A Wilson - 2/22/2010

Question
Solving first-degree equations   

    3x-2=16
       +2  +2        what are these +2's ?     
       3x=18

       3x = 18
        3      3

         x=6
Can you tell me what the +2's are doing in the second line down?  There is supposed to be a line (division line?) under them.   Thank you so much!   Tregg  I'm trying to brush up on algebra and came across this.  I understand the rest of it.

Answer
The are being added to both sides of the equation.
On the left side, there is a -2 in the top line, so they are adding 2 to get rid of it.
In doing this, 2 must also be added to the other side, so 16+2=18.

In the next case, they are dividing both sides by 3.
Note that 3/3 is 1, so all that is left is 1x, which is just written as x.
On the other side, 18/3 = 6.