math

[leslie]

I'm doing the practicse test for college entrance exams

can someone explain to me how

5x^2/25x+5x^2 is solved?

 

[leslie]

if ax=c-x then x=



I have the answers, I just don't get how to get there on some of these...and that's scary

 

[leslie]

getting frustrated...

a^2/9 - 4/25 in a factored form is -

 

[leslie]

if 4x/5=11 + x/4 then x=

it's all these rules I've forgotten...one I hear them again I think I'll be ok...

 

[leslie]

last one I don't get...

if m=1/3rb^2 then b=

 

[Nixy]

OK, I will start from post one and explain each one

Styarting in the next post

 

[Nixy]

I'm doing the practicse test for college entrance exams

can someone explain to me how

5x^2/25x+5x^2 is solved?

So, essentially you have:

(5*x*x)/(25*x + 5*x*x)

"dividing out" a factor of 5x you get:

x/(5 + x)

If that is all the question is I think that would be as far as you woudl be expected to go

 

[Nixy]

if ax=c-x then x=



I have the answers, I just don't get how to get there on some of these...and that's scary

ax = c - x

First thing to do is to make sure all the variables (x) are on the same side. Keeping in mind that what you do to one side you must do to the other.

So, ax + x = c - x + x

Leaving you with: ax - x = c

Common factor the x gives you : x(a - 1) = c

Therefore: x = c/(a - 1)

 

[Nixy]

getting frustrated...

a^2/9 - 4/25 in a factored form is -

(a^2)/9 - 4/25 is a difference of squares since all the terms have perfect roots. The formula for factoring a difference of squares is:

a^2 - b^2 = (a - b)(a + b)

So, (a^2)/9 - 4/25 = (a/9 - 2/5)(a/9 + 2/5)

 

[Nixy]

if 4x/5=11 + x/4 then x=

it's all these rules I've forgotten...one I hear them again I think I'll be ok...

4x/5 = 11 + x/4

First step is to get a common denominator. The LCD for 5, 1 and 4 woudl be 20.

So, 16x/20 = 220/20 + 5x/20

This is the same as: 16x = 220 + 5x

From here you rearrange and solve:

16x - 5x = 220 +5x - 5x
11x = 220
x = 20

 

[greenfreak]

Man, I was terrible in math, wish I could help too! But it looks like you're in good hands.

 

[Nixy]

last one I don't get...

if m=1/3rb^2 then b=

m = 1/3rb^2

You can use cross mutilplication here. The general rule is:

If a/b = c/d, then ad = bc

So, m(3rb^2) = 1
Since it's multiplication you can move the brackets whereever you want since they don't reall yhave a purpose except to visually seperate.

So, (m3r)b^2 = 1
Divide each side by (m3r) and you are left with b^2 = 1/(m3r)

Therefore b = Square root of (1/(m3r))

 

[Nixy]

If you need anything else I will be back and forth here all day and also might have ICQ on. i am going to PM you my work email though because excluding my hour lunch you should beable to reach me at that right up until 5pm

 

[leslie]

I think I have a lot of studying to do...

I aced this test 10 years ago and now I feel like I know nothing again

but seeing it all broken down again helped...now I am remembering

 

[Argus]

clever nixy

 

[Nixy]

Glad I could be of assistance Les

 

[Neo]

now i remember why i didnt want anything to do in the accounting or scientific field. I hated all that rubbish back then and still do. It was one of those things i learned to get the work done and then erased it from my memory banks when finished.
Now the boys are in school and ill prolly have to relearn some of it to help them with homework.

 

[Nihilistic]

is that like, polynomials or something?

 

[Nixy]

ROFL! That is the quote of the day!!!

 

[Stop Laughing]

Damn, and Huge isn't here for it.