Sei Zu Raku
Here's a math problem for you guys...It may seem pretty easy, and you might just think, "WTF? This girl is stupid..."
But it's more than 6 months since I've learned this stuff. So, I can't remember how to do some of it....X3
Okay...
lc-3l less than or equal to 4
Uh, I couldn't find a less than or equal to sign, so I had to write it, hope it's understandable. What I don't understand about this equation is the absolute value bars, I mean, I could do it, but I don't know what to do with the absolute value bars...
Also:
l2x+5l less than or equal to 9
(I need to know what to do if you have a coefficient)
Then there's:
t= 2 5
Uhm, the twist is, that the 't' and the '5' are under square root radicals.
x7
The x is no multiplied by 7, the 7 is an exponent, and it is all under a square root radical. I forgot how to do these too....
2(12 + 8 )
The 2, 12, and 8 are under square root radicals...I've forgotten so much about this stuff.
icon_gonk.gif
Uhm, hope you guys can help me.
It's been 6 months for you, about 4 and a half years for me XD
But I think I can help. I'll do each problem and then attempt to explain why, so that you hopefully learn something from the experience ^_^
1) |c-3| (less than or equal to) 4
Answer: -1 < c < 7 ----> The '<' symbols are 'less than or equal to'
The absolute value bars in this problem change the question a bit. When you are solving for a variable (c) when it's within absolute value bars, you have to realize something.
When a variable is within absolute value bars, there is a range of possible answers.The reason behind this is the function of absolute value bars. You know that when a problem has an absolute value symbol in it that the whole term becomes positive, right? For example:
|2-3|
The abs. val. bars act as a set of parenthesis. You take care of everything inside of them first. This then becomes:
|-1|
The abs. val. bars then make everything within it positive. This then becomes:
1
So, let's look back at out original problem. We have |c-3| (less than or equal to) 4. The question is asking you, "What numbers can you put in for 'C' will give you an answer that is less than or equal to 4?"
Well, you know that 7 - 3 = 4. So, 7 is the highest possible answer, since you can't go above an answer is 4.
So far our answer will be: c (less than or equal to) 7.
But here is where the absolute value bars come into play. The abs. val. bars will turn any negative number into a positive one. It cancels out the negative sign. So, you should know that there is a
negative answer for c that fits the answer. Now you have to ask yourself, "Hmm... What negative number fits in for 'c' that will give me an answer of 4?"
Try -1.
|c-3| less than or equal to 4
|-1 - 3| less than or equal to 4
|-4| less than or equal to 4
4 less than or equal to 4
Remember, the abs. val. symbol turns the number positive.
So, since your answer of "4" is less than or equal to 4, you have the lower range of your problem. Your final answer will be:
-1 < c < -7 , where the '>' are 'less than or equal to'.
This just means that 'c' needs to be any number between those values to satisfy the answer to this problem.
Hope that helps.
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2) Okay! All of my notes from before apply here, so let's go through the problem.
Remember:
The problem does not change, even if you have a coefficient.With that in mind, we have:
l2x+5l (less than or equal) to 9
Re-word the question if it will help you. It is asking: "What range of numbers will give us an answer that is less than or equal to 9?"
First, find the high end of this range. What positive number will givev you the answer of 9? An easy way to do this is to remove the abs. val. symbol and set it equal to 9. So, you get:
2x+5=9
2x=4
x=2
So, you know that 2 is the high range of your answer. So far, the answer is:
x (less than or equal to) 2
But remember the lower range! There is a negative number that will also give you an answer of 9. So, you have to ask yourself, "Hmm... What negative number will make the equation inside of the abs. val. symbols simplify down to -9?" (The absolute value bars will cancel out the negative sign, so you want to achieve the answer that is the negative of what you're looking for. You're trying to get '9', so you want to get '-9' inside the abs. val. bars. )In this case, it is -7:
|2x+5|
|2(-7)+5|
|-14+5|
|-9|
9
You now have the lower end of your range! Your full answer is:
-14 < x < 2 , where '<' is 'less than or equal to'.
Hope that helps.
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3) (radical)t = 2 (rad) 5
You have to solve for 't'. To do this, you know that 't' has to be on it's own. It can't be squared, it can't be under a radical, it can't be on top of a building performing a sonnet. 't' has to be on its own.
Since 't' is under a radical, you need to perform the opposite function of the radical to cancel it out
to both sides of the equation. Remember, what you do to one side you have to do to the other.
And what function is the opposite of a radical? Taking the 'square' of something.
So, you need to square both sides of the equation:
([rad] t)^2 = (2 [rad] 5)^2
**Note: The '^' symbol is called a 'carrot', and it means 'to the ____ power'. It's used for square roots.
So, you know that the square and the radical cancel each other out. Then, you need to simplify the other side as well. You know that '2' and '(rad)5' are being multiplied, so you need to distribute the squared term through to both of them separately. You get:
t = 2^2 x ([rad]5)^2
Simplify:
t = 4 x 5
Then, simplify again:
t = 20
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4) x^7, all under a radical. We'll express this as: (rad)[x^7]
Okay! I'm guessing you have to simplify this.
The way you do this problem requires you to realize something: The 'x' is absolutely irrelevant until the very end. You are just dealing with the '7' and the radical.
Now, you need to break up 'x^7' as far as you can using the rules of exponents. In this case, you know that when you have an exponent multiplied to an exponent, you add the numbers together. So, you can break up x^7 into:
(x^2) x (x^2) x (x^2) x (x^1) ----> The 'x' outside of parenthesis are multiplication symbols.
Breaking up x^7 into those littler exponents makes this problem a lot easier to deal with. You'll see why now.
The next step is applying the radical to these little exponents. Oh my god! Look! Taking the radical of 'x^2' just leaves 'x'! How simple!
^_^
So, after doing this, you are left with:
(x) x (x) x (x) x (rad[x]) --> The 'x' outside of parenthesis are multiplication symbols.
Simplify it again:
(x^3) x (rad[x])
At this point, you've simplified the problem as far as you can go. So, your final answer should be left as:
(rad x) x^3
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5) [rad]2([rad]12 + [rad]8 )
Okay. Another simplification problem. When you're dealing with radicals, it's easy to think of it as any other normal problem. You go about them the same way, it's just an added symbol that you have to take into account.
The first step is to distribute the [rad]2 throughout the parenthesis, just like any non-radical problem:
([rad 2] x [rad 12]) + ([rad 2] x [rad 8])
I put the parenthesis to remind you that you have to deal with the multiplication side of things first, before addition.
Okay, so now you have this jumbled mess of numbers, symbols and math signs. What do you do?!? Well, you follow this like any other normal problem. If the radicals weren't there, you would multiply the numbers together, right? So, that's exactly what you do. Remember: When dealing with radicals, you need to simplify them first. So, take each one and simplify it as far as it can go:
[rad 2] --> Simplified as far as it can go.
[rad 12] --> 2 [rad 3]
[rad 8] --> 2 [rad 2]
So, first you need to multiply ([rad 2] x [rad 12]). For radicals, you can just multiply what is underneath them together to get a single digit, and then simplify it down:
[rad 2] x 2[rad 3] = 2 [rad 6]
**Note: [rad 6] can't be simplified, so you're all set.
Now you need to multiply ([rad 2] x [rad 8]):
[rad 2] x 2[rad 2] = 2 [rad 4]
Remember to simplify!
[rad 4] = 2
So, your answer for the second part reads:
2 [rad 4] = 2 x 2 = 4
Now, you need to add the resulting answers together to finish the problem. You had:
([rad 2] x [rad 12]) + ([rad 2] x [rad 8])
Which led to:
2[rad 6] + 4
Guess what? You're done! You can't simplify that anymore, so your final answer is:
2[rad 6] + 4
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I really hope that helped Sei. I wish you luck on your mathematical quests in the future!