Showing posts with label Linear Equations. Show all posts
Showing posts with label Linear Equations. Show all posts

Monday, March 18, 2013

Linear Equations Math

Introduction to linear equations in math:

A linear equations is an algebraic equation in which each term is either a constant or the product of a constant and (the first power of) a single variable. Linear equations can have one or more variables. Linear equations occur with great regularity in mathematics. The general form of the liner equation is y =mx +b. Otherwise it can be written as ax + by=c. Here we are going to how to solve the liner equation in math and its example problems. (Source from Wikipedia)


Solving method for linear equations in math:


Elimination method
Substitution method

Example problems for solving linear equations in math:


Example: 1

Solve the following liner equation using elimination method 2x+3y = 5 and x + y = 2

Solution:

2x+3y = 5 -----------------------1

x + y = 2 -------------------------2

Multiply equation(2) by 2, we get

2x + 2y = 4 ----------------------3

Take equation 1 and 3 subtract equation 3 from 1 we get

2x+3y = 5

2x + 2y = 4   (change the sign and add)

--------------------

y = 1

----------------

Now we have to find the x value

Substitute y value in to the equation 1 we get

2x + 3y = 5

2x + 3 (1) = 5

2x + 3 = 5

Add both sides -3 we get

2x + 3 - 3 = 5 - 3

2x = 2

Divide both sides 2 we get

x = 1

Therefore the solution of the given liner equation is x = 1 and y = 1

Example: 2

Solve the following liner equation using substitution method

x+4y = 10

x+12y = 20

Solution:

x+4y = 10 ----------------------- 1

x+12y = 20 ----------------------2

Form equation 1 we can write

x = 10 - 4y -----------------------3

Substitute the x value into the equation 2

10-4y+12y = 20

10 + 8y = 20

Add both sides -10

8y = 20-10

8y = 10

y = `10 / 8`

y = `5/4`

Substitute y value into equation 3 we get

x = 10 – 4`(5/4)`

x = 10 -`20/4`

x = `(40 - 20) / 4`

x = `20/4`

x = 5

Therefore the solution of the given liner equation is x = 5 and y =` 5/4`

Thursday, March 26, 2009

Problem on Linear Equations to Find the Unknown Value of a Variable

Topic : Linear Equations

Problem : Solve 2x + 3y = 4 and 3x - 2y = 1

Solution :
2x + 3y = 4 --------------(1)
3x - 2y = 1 --------------(2)

Multiply equation (1) by 3 and equation (2) by 2 then,
6x + 9y = 12 ----------- (3)
6x - 4y = 2 ------------ (4)
Subtraction (4) by (3) then,
+13y = 10
y = 10/13

Substitute the value of y in equation (1)
2x + 3y = 4
2x + 3(10/13) = 4
2x + 30/13 = 4
2x = 4 - 30/13
2x = (52-30)/13
2x = 22/13
x = 11/13