Keelen,

Stevie,

Nic, and

Marissa,

This yellow tile represents a POSITIVE one.

This red tile represents a NEGATIVE one.

This is also a MYSTERY NUMBER, but it is a negative X.

This is a MYSTERY NUMBER. Since we don’t know the value of it, it is called X.

Additive Inverse: A pair of numbers or expressions to a sum of zero.

Example: If Johnny had one apple, and Bobby took it away, Johnny has ZERO apples.

That process is called ZEROING OUT.

Therefore, if you have a positive One Square and subtract One square Square, ,(or add a negative that equals the same value.)

This line means the equal sign (=)

You put tiles on both sides of the boxes. They represent an equation.

This Means:

This is a POSITIVE 2x

This is just a POSTIVE 2.

There is a NEGATIVE X in this box, plus the Negative 1.

This means it’s a Positive 2X minus a Negative 1

We now have to find out what X means in an equation.

If the equation is:

Take away 5, or add a negative 5 (-5), on both sides to ZERO OUT.

Now you can see that in the boxes, there are 3 different groups with one in each group so equals 5!

When “X” is on both sides of the equation………..

2x-4=x+3

In order to solve this equation you need to zero out. So, you add four to each side of the equation

to get rid of the –4.

*You always want to get rid of negatives first.

Try this one on your own!

This is how it looks on an equation box!

Remember zeroing out and getting the x off the right side as a priority!

Remember to ZERO OUT all of the X’s first, then the NUMBERS!

Now how did we figure that out?

This equation will NOT be able to split into even groups. So, we take a different route.

We start this equation by subtracting or adding a negative X to each side because of the X on the right. Then you begin zeroing out: X-4 by adding 4 to each side of the box.

The dotted line shows that there are TWO groups of 2x+4

Now how will you ever be sure that your answer is

right?

Next slide….

Here’s an even equation!

Remember to use additive inverse when trying to find out what X means.

Now to zero out the X’s, you have to subtract an X from each side, to make sure that only one X is left on one side.

We zeroed out the X=

Then, since the X is multiplied by two, you divide both sides by two to zero the 2X out..