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Mathematics 8 Online
OpenStudy (horsegirl27):

Please help medal and fan!!!!! I'm so confused how to do this type of problem, please explain!!!!

OpenStudy (horsegirl27):

OpenStudy (horsegirl27):

@misty1212 this one is different so idk :/

OpenStudy (horsegirl27):

@BlossomCake @bohotness @Compassionate @InExileWeTrust @EclipsedStar

OpenStudy (horsegirl27):

@misty1212

OpenStudy (horsegirl27):

Somebody please help me!!!!

OpenStudy (anonymous):

say something @plusky

OpenStudy (anonymous):

so ik can give you a medal

OpenStudy (horsegirl27):

don't just give them a medal

OpenStudy (horsegirl27):

That is breaking the CoC ._. .-.

OpenStudy (anonymous):

no its because he help me on my other question and i said i was going to give him a medal but i acedently closed it.

OpenStudy (horsegirl27):

oh, u still can give medals in closed questions

OpenStudy (horsegirl27):

Go to closed questions, or to your "asked questions" on your profile

OpenStudy (horsegirl27):

@iGreen @animal_lover36 @thomaster @TheEdwardsFamily Can someone help me?

OpenStudy (phi):

they want you to first learn how to "rewrite" radicals using exponents Here is the rule: \[ \sqrt[a]{b}= b^\frac{1}{a} \]

OpenStudy (horsegirl27):

ok

OpenStudy (phi):

try to match up your problem with the rule: \[ \sqrt[4]{9} \] which number matches with "a" which number with "b"

OpenStudy (horsegirl27):

9 is b, 4 is a

OpenStudy (horsegirl27):

9 1/4

OpenStudy (phi):

now use the other side to write it as \[ 9^\frac{1}{4} \] so far , so good

OpenStudy (phi):

you should put in an ^ like this: 9^(1/4) so we know the 1/4 is an exponent

OpenStudy (phi):

if you don't see a number in the "a" position, we *assume it is 2*

OpenStudy (horsegirl27):

ok

OpenStudy (phi):

so can you translate \[ \sqrt{9} = \sqrt[2]{9}= ?\]

OpenStudy (phi):

match \[ \sqrt[2]{9} \] to the rule

OpenStudy (horsegirl27):

9^(1/2)

OpenStudy (phi):

yes. that (for the moment) takes care of the top. But we will return to that later now for the bottom \[ \sqrt[4]{9^5} \] we use the same rule, except "b" is not just 9, it is 9^5

OpenStudy (horsegirl27):

ok but then how does the 1/4 work with the 9^5?

OpenStudy (phi):

you put parens around 9^5 and think of it as "one thing" then write the exponent 1/4 in the upper right side in little numbers

OpenStudy (horsegirl27):

ok so like (9^5)^1/4?

OpenStudy (phi):

yes, exactly

OpenStudy (horsegirl27):

ok

OpenStudy (phi):

but (of course) there are ways to "simplify" that. it turns out, if you have \[ \left(a^b\right)^c \] you can rewrite it as \[ \left(a^b\right)^c = a^{bc}\]

OpenStudy (horsegirl27):

oh, ok

OpenStudy (phi):

try to match up \[ \left(9^5\right)^\frac{1}{4} \] with the rule

OpenStudy (horsegirl27):

so 9^5 1/4?

OpenStudy (phi):

yes if you mean 5 times 1/4 for the exponent. but you can write \[ 5 \cdot \frac{1}{4} = \frac{5}{4} \] if you remember how to multiply a number times a fraction

OpenStudy (phi):

in case you did not know, in algebra (i.e. when we write rules using letters) the bc in the rule is short for b*c (b times c)

OpenStudy (horsegirl27):

ohh ok yeah i know about the bc and b*c

OpenStudy (phi):

now let's write what we have so far \[ \frac{ 9^\frac{1}{4}9^\frac{1}{2} }{9^\frac{5}{4}} \]

OpenStudy (horsegirl27):

ok

OpenStudy (phi):

when you multiply numbers with the *same base* (and here we have 9 as the base) we can add the exponents. for the top we can add 1/4 + 1/2 can you do that ?

OpenStudy (horsegirl27):

yeah 3/4

OpenStudy (phi):

that means the top can be rewritten \[ 9^\frac{1}{4}9^\frac{1}{2} = 9^\frac{3}{4} \]

OpenStudy (horsegirl27):

ok

OpenStudy (horsegirl27):

Then it will be 9 3/4 over 9 5/4

OpenStudy (phi):

yes, good. you have \[ \frac{ 9^\frac{3}{4} }{9^\frac{5}{4}} \] the other rule, is if you divide (and you have the same base), subtract the "bottom" exponent from the top exponent

OpenStudy (horsegirl27):

9 8/4 then simplified to 9^2

OpenStudy (phi):

you added?? (which you would do if the problem was \( 9^\frac{3}{4} 9^\frac{5}{4} \) ) remember: subtract if you are dividing

OpenStudy (phi):

if you divide (and you have the same base), subtract the "bottom" exponent from the top exponent

OpenStudy (horsegirl27):

oh, sorry

OpenStudy (horsegirl27):

So -2/4 9^-1/2?

OpenStudy (phi):

yes. You had to use every trick in the book to do this problem

OpenStudy (horsegirl27):

ok. Thanks for helping!! I finally understand

OpenStudy (phi):

it might help you to remember these rules if you remember a simple problem for example \(3^2 \) means 3*3 if you multply \( 3^2 \cdot 3^1\) you know the answer is 3*3*3, which is \(3^3\) and that might help you to remember to add the exponents. or \[ \frac{3\cdot 3}{3} = 3 \] or using exponents \[ \frac{3^2}{3^1}= 3^1 \] notice you subtract exponents

OpenStudy (horsegirl27):

ok

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