Showing posts with label algebra help. Show all posts
Showing posts with label algebra help. Show all posts

Wednesday, August 26, 2009

A word problem on sets

A set is a collection of distinct objects, considered as an object in its own right. Sets are one of the most fundamental concepts in mathematics. Although it was invented at the end of the 19th century, set theory is now a ubiquitous part of mathematics, and can be used as a foundation from which nearly all of mathematics can be derived. In mathematics education, elementary topics such as Venn diagrams are taught at a young age, while more advanced concepts are taught as part of a university degree.

Here is an example from algebra 1 word problems


Question:-


In a school there are 20 teachers who teach mathematics or physics,of these ,12 teach mathematics and 4 teach both physics and mathematics .How many teach physics

Answer:-

The total number of students =20 (this is we call what is Universal Set U)

Let M be the teachers who teach mathematics

and P be the teachers who teach physics.

the word 'or' gives a clue of union and the word 'and' gives a clue of intersection.

n(M U P)=20

n(M)=12

n(M Ω P)=4

you can see a example of Venn diagram

using the formula

n(M U P)=n(M)+n(P)-n(M Ω P)

20 = 12+n(P)-4

20 = 8+n(P)

subtract 8 on both sides

12 = n(P)

So 12 teachers teach physics

Tuesday, May 19, 2009

A problem on Simplifying Algebraic Fractions

Fractions is a basic section of math where student get to learn how to do fractions, types of fractions and how to simplify fractions involving algebraic terms or numeric terms as shown in the below problem.


Topic : Simplifying Algebraic Fractions

Below problem is an algebra question which explains how to do fraction.

Problem : Show the steps that you would take to solve the following algebraically




What potential solution did you obtain? Explain why this is not a solution.

Solution :










=> 3 * 2 = 2x - 3x + 9

=> 6 = - x + 9

=> - x + 9 = 6

=> - x = 6 - 9

=> -x = - 3

=> x = 3

This is not a solution because at x = 3, the denominators of the terms at the right hand side and the left hand side become ‘zero’. So, x = 3 is only a potential solution and not a solution.