8th Grade ... Pre Algebra ... HELP!

• Sep 18th 2008, 06:01 PM
tatsing11
8th Grade ... Pre Algebra ... HELP!
(Worried) I have a math test tomorrow and idk how 2 do sum stuff.
im having trouble with how to:
Evaluate decimal numbers with a positive power
Evaluate decimal numbers with a negative power
Evaluate negative numbers with positive exponents
Evaluate negative numbers with negative exponents

I litterally skipped 2 grades worth of math. I skipped anything I would have learned in 6th and 7th grade math . (Wink) unfortunately, thats mostly what i need 2 be able 2 do this. I would luv if someone could SIMPLY xplain 2 me how to do these.(Bigsmile)
Thx so much,
Clueless
• Sep 18th 2008, 06:03 PM
Jhevon
Quote:

Originally Posted by tatsing11
(Worried) I have a math test tomorrow and idk how 2 do sum stuff.
im having trouble with how to:
Evaluate decimal numbers with a positive power
Evaluate decimal numbers with a negative power
Evaluate negative numbers with positive exponents
Evaluate negative numbers with negative exponents

I litterally skipped 2 grades worth of math. I skipped anything I would have learned in 6th and 7th grade math . (Wink) unfortunately, thats mostly what i need 2 be able 2 do this. I would luv if someone could SIMPLY xplain 2 me how to do these.(Bigsmile)
Thx so much,
Clueless

when you say "evaluate" what to you mean?

can't you just plug them into a calculator, or do you have to work them out by hand? do you know what raising a number to a positive power does? what about a negative power?
• Sep 18th 2008, 06:14 PM
tatsing11
Evaluation
by evaluate, i mean figure out the value of the number. such as this prob:
Evaluate: 32 would be 9. thats what our math teachr says so yep and um
im okay with positive numbers with negative powers and stuff but i have no idea about decimals or neg numbrs and neg powers

• Sep 18th 2008, 06:26 PM
Jhevon
Quote:

Originally Posted by tatsing11
by evaluate, i mean figure out the value of the number. such as this prob:
Evaluate: 32 would be 9. thats what our math teachr says so yep and um
im okay with positive numbers with negative powers and stuff but i have no idea about decimals or neg numbrs and neg powers

well, i am trying to get at what level of sophistication you require, but you are not telling me much

all i can say is that you treat the decimals just as you would whole numbers

example, $\displaystyle 3.02^2 = 3.02 \times 3.02 = 9.1204$

or, $\displaystyle 3.02^3 = 3.02 \times 3.02 \times 3.02 = 27.543608$

etc

if you have $\displaystyle 3.02^{-2} = \frac 1{3.02^2} = \frac 1{9.1204} = 0.1096 \dots$
• Sep 19th 2008, 02:25 AM
tatsing11
srry
srry dude but i need an xplanation stilll. im only in 6th grde but im in 8th grade math so i stll dk how 2 do it
• Sep 19th 2008, 01:49 PM
weakmath
let me try to make this easier:

power means multiplying by it self
"to the power of" is often replace by ^

ex. 3 "to the power of" 4
3 ^ 4
3 multiplies by it self 4 times = 3x3x3x3 = 81

ok here are some rules you just have to memorize

1. if you have a negative number and you take the power of a odd number you will end up with a negative number

(-3) ^ 3 = (-3)x(-3)x(-3) = -27

2. if you have a negative number and you take the power of a even number you will end up with a positive number
3 ^ 4 = 3x3x3x3x = 81

3. when you take it to the power of a negative number, basicly just treat the minus sign as 1 over "the number"
3 ^ (-2) = 1 over 3^2 = 1/3 x 1/3 = 1/9
• Sep 19th 2008, 02:26 PM
icemanfan
Also, evaluating a number to a fractional power involves taking roots. For instance, $\displaystyle 3^{1.5} = 3\sqrt{3}$.
• Sep 22nd 2008, 06:34 AM
sandgaara
Hi (Hi)well you see if you are haveing problems with this just do what i do talk to the teacher and ask if you can study more befor you take the tes or you can just ask to retake the test me my self have a test to take next class to day and it is all about this stuff i know all of it so im shour i gunna get an A(Happy)
• Sep 22nd 2008, 06:45 AM
sandgaara
plz help
can any one help me with a problem like this

5 to the 6th power times 6 to the 5th power divided by 9 to the 3 power

my teacher said if we can simplfie it and figer it out we get NO HOMEWORK FOR THE REST OF THE YEAR(Bow)(Bow)(Bow)
• Sep 22nd 2008, 06:49 AM
sandgaara
(Worried)well this is my last post i might talk to you guys later i guess Bye(Hi)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bo w)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bo w)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)(Bow)
• Sep 22nd 2008, 08:47 AM
masters
Quote:

Originally Posted by tatsing11
srry dude but i need an xplanation stilll. im only in 6th grde but im in 8th grade math so i stll dk how 2 do it

Sounds like you need some serious help in writing in plain English!
• Sep 22nd 2008, 12:32 PM
Jhevon
Quote:

Originally Posted by sandgaara
can any one help me with a problem like this

5 to the 6th power times 6 to the 5th power divided by 9 to the 3 power

my teacher said if we can simplfie it and figer it out we get NO HOMEWORK FOR THE REST OF THE YEAR(Bow)(Bow)(Bow)

well that's not fair.

by the way, post new questions in a new thread.

i will start you off though, you finish up. start by writing 6 as 3*2 and writing 9 as 3^2