### Math with Mea

Posted:

**Wed Jan 04, 2017 1:35 pm**Introduction

I thought I'd just post a few mathematical stuff and explain as best as I can.

Finding x

This variable is pretty popular and finding x can mean anything. That's why it's a variable. It could be a y if you wanted it to be, or a z, or even a happy face. Whatever you choose for your variable, make sure you understand why it's there. You can really just think of variables as placeholders. Let's use an example.

If you know basic arithmetic, which I'm sure you do, then you already know what x is. Still, you have to isolate x. What that means is that 5 needs to end up on the opposite side of the equation. How do you do that? Well, what plus 5 is 0? The answer is simple. -5! The equation will look like this.

If we subtract a number from one side, we have to do it with the other side. Why? Think of a scale that is evenly balanced. On the left side we have a cube that has x on it. We also have an additional 5 cubes that are smaller. On the right side of the scale you have 20 cubes. If you were to take 5 cubes away from the left side, the scale would tip so that the right side would drop down and the left side would rise up, since the left would be lighter than the right. In order to keep it evenly balanced, we must remove 5 cubes from the right. Algebraically, it looks like this.

Next, we subtract both sides, which gives us this result below.

So the answer we end up with is 15. If we want to make sure this is the correct answer, we would remove the variable and put 15 in its place, which would look like this.

So x is 15.

What happens if we have more than one number in the equation? The method wouldn't be that different. Let's use the same example.

Before we isolate x, we need to do something about the two numbers. If you think that you should add the two numbers, you'd be correct. We'd end up with the following.

Using what you know from the previous example, you will subtract both sides by 9.

Is this true? Let's see.

11 is the correct answer. If you're curious about how this would work out if you added instead of subtracted, then the idea is pretty much the same. I'll use the first example to give an idea.

Instead of subtracting both sides, we now have to add for the same reason as given when I used the scale analogy. If we added 5 cubes to the left and not the right, then the scale would be uneven.

Like before, if we want to make sure we have the correct answer, then we will take our final result and replace x.

Keep in mind that this is for addition and subtraction, not multiplication and division. I may post more later.

I thought I'd just post a few mathematical stuff and explain as best as I can.

Finding x

This variable is pretty popular and finding x can mean anything. That's why it's a variable. It could be a y if you wanted it to be, or a z, or even a happy face. Whatever you choose for your variable, make sure you understand why it's there. You can really just think of variables as placeholders. Let's use an example.

- x + 5 = 20

If you know basic arithmetic, which I'm sure you do, then you already know what x is. Still, you have to isolate x. What that means is that 5 needs to end up on the opposite side of the equation. How do you do that? Well, what plus 5 is 0? The answer is simple. -5! The equation will look like this.

- x + 5 - 5 = 20 - 5

If we subtract a number from one side, we have to do it with the other side. Why? Think of a scale that is evenly balanced. On the left side we have a cube that has x on it. We also have an additional 5 cubes that are smaller. On the right side of the scale you have 20 cubes. If you were to take 5 cubes away from the left side, the scale would tip so that the right side would drop down and the left side would rise up, since the left would be lighter than the right. In order to keep it evenly balanced, we must remove 5 cubes from the right. Algebraically, it looks like this.

- x + 5 - 5 = 20 - 5

Next, we subtract both sides, which gives us this result below.

- x = 15

So the answer we end up with is 15. If we want to make sure this is the correct answer, we would remove the variable and put 15 in its place, which would look like this.

- 15 + 5 = 20
- 20 = 20

So x is 15.

What happens if we have more than one number in the equation? The method wouldn't be that different. Let's use the same example.

- x + 5 + 4 = 20

Before we isolate x, we need to do something about the two numbers. If you think that you should add the two numbers, you'd be correct. We'd end up with the following.

- x + 9 = 20

Using what you know from the previous example, you will subtract both sides by 9.

- x + 9 - 9 = 20 - 9
- x = 11

Is this true? Let's see.

- 11 + 5 + 4 = 20
- 16 + 4 = 20
- 20 = 20

11 is the correct answer. If you're curious about how this would work out if you added instead of subtracted, then the idea is pretty much the same. I'll use the first example to give an idea.

- x - 5 = 20

Instead of subtracting both sides, we now have to add for the same reason as given when I used the scale analogy. If we added 5 cubes to the left and not the right, then the scale would be uneven.

- x - 5 + 5 = 20 + 5
- x = 25

Like before, if we want to make sure we have the correct answer, then we will take our final result and replace x.

- 25 - 5 = 20
- 20 = 20

Keep in mind that this is for addition and subtraction, not multiplication and division. I may post more later.