MATH HELP PLEASE HELP Me!?

Question

Adding and Subtracting Fractions Help PLease!!!

1. n/ n-2 - 3n-1/n-2

2.5b+2 / 8 + 3b-4/10

3. Find the perimeter of a rectangle
length = 3a + 6/4
width = 2a-1/ 6


THANKS AGAIN!!!

Answer 1

PROBLEM 1:

Here you have the same denominators, so just combine the numerators:
n - (3n - 1)
--------------
n - 2

Now simplify the numerator (don't forget to distribute the minus sign):
-2n + 1
----------
n - 2

PROBLEM 2:

Here you need to get a common denominator. The lowest common multiple of 8 and 10 is 40.

5(5b + 2) / 40 + 4(3b - 4) / 40

Now combine the numerators:
5(5b + 2) + 4(3b - 4)
---------------------------
40

Distribute the 5 and 4 into the parentheses:
25b + 10 + 12b - 16
-------------------------
40

Combine like terms in the numerator:
37b - 6
---------
40

PROBLEM 3:

The answer is 2( L + W ):

L = (3a + 6) / 4
W = (2a - 1) / 6

The common denominator is 12:
L = 3(3a + 6) / 12
W = 2(2a - 1) / 12

Adding them:
3(3a + 6) + 2(2a - 1)
--------------------------
12

9a + 18 + 4a - 2
-----------------------
12

13a + 16
-----------
12

But this is L+W and you want double that:
2(13a + 16)
---------------
12

Cancel a 2 from top and bottom:
13a + 16
------------
6

SUMMARY:
1. (-2n + 1) / (n - 2)
2. (37b - 6) / 40
3. (13a + 16) / 6

Answer 2

1. n/ n-2 - 3n-1/n-2
n-3n+1/(n-2)
=(-2n+1)/(n-2)

2.5b+2 / 8 + 3b-4/10
5(5b+2)+4(3b-4)/40
25b+10+12b-16/40
=(37b-6)/40

3. Find the perimeter of a rectangle
length = 3a + 6/4
width = 2a-1/ 6
perimeter=3a+6/2+2a-1/3
3(3a+6)+2(2a-1)/6
=(13a+16)/6

Answer 3

It's not entirely clear what you mean. Next time brackets may make it clearer.

i'll asume it means n/(n-2) - (3n-1)/(n-2)

If you look at the two denominators (bottom lines), you'll see they are the same.

This is a bit like being asked to do the sum 7/9 - 5/9 and you it exactly the same way.

(7-5)/9
=2/9

There is a denominator which is (n-2), so write it on the bottom line

Now write on the top line

n - (3n-1)
=n -3n+1......remember that a minus sign outside the bracket changes the signs inside the bracket

=-2n+1...for the numerator (top line)

whole answer is

(-2n+1)/(n-2)

this looks better as

(1-2n)/(n-2)

You try the next one.....Hint. In this sum the denominators are different. This is like doing

2/3 + 1/4

The last sum needs you to write two terms in brackets and multiply them out.

Clue...when i was young , i was taught to draw a face round the brackets. If you can't do the sum, ask your teacher to show you how to draw the face

Answer 4

I see you got a few good answers here, you can also find some good online explanations for just about any math topic by putting subject tutorial in your search window.
A good online explanation helps, because it's a lot easier to read the fractions and follow the explanations. When something's hard to read, as it is here, it looks a lot harder than it is.
When I put adding and subtracting fractions in my search window, here's a few things that came up... Good luck!
--------- Search Results (quote)---------------------
Adding algebraic fractions - A complete course in algebra
ADDING ALGEBRAIC FRACTIONS. Different denominators -- The LCM. 2nd level. THERE
IS ONE RULE for adding or subtracting fractions: The denominators must be ...
http://www.themathpage.com/alg/add-algebraic-fractions.htm

Algebraic Fractions
In order to add or subtract, or "combine", algebraic fractions, a common denominator
is needed. (This is the same process you use with adding and ...
http://regentsprep.org/Regents/math/fractions/addsubt.htm

Algebraic Fractions
Practice Page. Math A. Practice Adding and Subtracting Fractions. Add and/or
subtract these algebraic fractions: (It’s OK to have an improper fraction!) ...
http://regentsprep.org/Regents/Math/fractions/Paddsubt1.htm

Algebra: Fractions - Math for Morons Like Us
When adding or subtracting fractions from other numbers, and especially ...
As we move toward more complex Algebra, you will come across fractions that have ...
http://library.thinkquest.org/20991/alg/frac.html

College Algebra Tutorial on Adding and Subtracting Rational ...
College Algebra Tutorial 10: Adding and Subtracting Rational Expressions ...
Step 2: Write equivalent fractions using the LCD if needed. ...
http://www.wtamu.edu/academic/anns/mps/math/ mathlab/col_algebra/col_alg_tut10_addrat.htm

Intermediate Algebra Tutorial on Adding and Subtracting Rational ...
Intermediate Algebra Tutorial 33: Adding and Subtracting Rational Expressions
... Now the two fractions have a common denominator, so we do not have to ...
http://www.wtamu.edu/academic/anns/mps/math/ mathlab/int_algebra/int_alg_tut33_addrat.htm

Fractions
Adding Algebraic Fractions. Objective: Students will be able to add algebraic
fractions. Two or more algebraic fractions can be added in five steps. ...
http://www.gomath.com/htdocs/lesson/fraction_lesson3.htm

Cool math Algebra Problem Generator - Adding and Subtracting ...
This Algebra Cruncher generates an endless number of practice problems for adding
and subtracting algebraic fractions -- with solutions! ...
http://www.coolmath.com/algebra/cruncher/algfrac1.htm

edHelper.com - Polynomials
Return to Algebra Worksheets · Return to Math. Name _____________________________
... Fractions (Answer ID # 0303796). Complete and write in lowest terms. ...
http://www.edhelper.com/polynomials307.htm

Algebra Facts: Adding and Subtracting Fractions
Algebra Facts Adding and Subtracting Fractions. Adding and subtracting fractions
is not so hard once you understand why the rules for fractions work the way ...
http://www.mathmistakes.info/facts/ AlgebraFacts/learn/fr/add.html
-----------------(end quote) -----------------------------

Answer 5

1. (n-3n-1)/n-2 = (-2n-1)/n-2

2. 5(5b+2)/5(8) + 4(3b-4)/4(10)
=(25b+10)/40 + (12b-16)/40
=(37b-6)/40

3. 2((3a+6)/4) + 2((2a-1)/6)
=(6a+12)/4 + (4a-2)/6
=3(6a+12)/3(4) + 2(4a-2)/2(6)
=(18a+36)/12 + (8a-4)/12
=(26a+32)/12
=(13a+16)/6