Lesson Simultaneous Equations Part 1

Source code of 'Simultaneous Equations Part 1'

This Lesson (Simultaneous Equations Part 1) was created by by Quadratic1600(28)

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About Quadratic1600: SQR -1 love Maths - I just do the odd maths question for fun in my spare time. My favourites vary from Probability to Quadratics and Completing the square but also equations

This lesson is aimed for those who want an introduction in to simultaneous equations. These equations can be used to find points of intersection on a graph or in many cases they are used to solve age problems which I will explain in another lesson.

There are several ways to solve these equations

Substitution (which is my favourite)
Elimination
Using a graph (This is time consuming)

You can also label the equations (1) and (2) which is useful when using the substitution method
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E.G. Substitution

x + y = 4 (1)
 y = 2 (2)

Ok so since y = 2 we can say x + 2 = 4 
Then x = 2 and y = 2
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Elimination

3x - y = 12  (1)
2x + y = 13  (2)

Add the two together and you cancel out y leaving 5x = 25 so x = 5

Then put x back in to find y

5 x 3 - y = 12
15 - y = 12
-y = -3
y = 3
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Graphs

We could plot the graph lines

3x - y = 12 rearranged in to y = 3x - 12
2x + y = 13 rearranged in to y = -2x + 13

However that is time consuming and from those graph lines it is a lot quicker to just say 
3x - 12 = -2x + 13

And by doing this you can then solve for x and then for y

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So these equations can be solved in several different ways (some quicker than others)
This lesson is just an introduction in to these equations so I am not going any further however I hope this lesson has answered any problems you have been having in the basic understanding of these equations.

Thank you