math

leslie

leslie

New Member
I'm doing the practicse test for college entrance exams :scared:

can someone explain to me how

5x^2/25x+5x^2 is solved?
 
if ax=c-x then x=

:mope:

I have the answers, I just don't get how to get there on some of these...and that's scary :(
 
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...
 
OK, I will start from post one and explain each one :)

Styarting in the next post :D
 
leslie said:
I'm doing the practicse test for college entrance exams :scared:

can someone explain to me how

5x^2/25x+5x^2 is solved?
Click to expand...

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 :)
 
leslie said:
if ax=c-x then x=

:mope:

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

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)
 
leslie said:
:(

getting frustrated...

a^2/9 - 4/25 in a factored form is -
Click to expand...

(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)
 
leslie said:
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...
Click to expand...

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
 
leslie said:
last one I don't get...

if m=1/3rb^2 then b=
Click to expand...

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))
 
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 :)
 
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 :retard:

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