STEP 1:

                             

We want these two numbers to be the same, but have opposite signs.  Then, we'll add them together and get 0.

Now, we add Row 1 and Row 2 -- just work straight down!  Then, you put Row 1 back to normal:

Row 1 back to normal Row 1 + Row 2

STEP 2:

Now, we work a bit backwards!

We want these two numbers to be the same, but have opposite signs.  Then, we'll add them together and get 0.

Now, we add Row 1 and Row 2 -- just work straight up!  Then, you put Row 2 back to normal:

Row 2 + Row 1 Row 2 back to normal

Continued on the next page