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Solving Equations www.ipracticeMath.com

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Page 1: Simultaneous equations

Solving Equations

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Page 2: Simultaneous equations

Determinant method of solving simultaneous

equations

If a, b, c and d are any four numbers, the value ad-bc is represented

|๐‘Ž ๐‘๐‘ ๐‘‘|

Page 3: Simultaneous equations

The value of the Determinant is ad-bc.

As it has two rows and two columns It is called as

determinant of order two

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Page 4: Simultaneous equations

where , , , , and are the real numbers such that

and and y are variables.๐“

simultaneous equations

๐‘Ž1๐‘ฅ+๐‘1 ๐‘ฆ=๐‘1

๐‘Ž2๐‘ฅ+๐‘2๐‘ฆ=๐‘2

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Page 5: Simultaneous equations

For equating the coefficients of y, let us multiply equation (1) by

and equation (2) by to get,

๐’‚๐Ÿ๐’™+๐’ƒ๐Ÿ๐’š=๐’„๐Ÿ ๐’‚๐Ÿ๐’™+๐’ƒ๐Ÿ๐’š=๐’„๐Ÿ

----------- 3

----------- 4

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Page 6: Simultaneous equations

 

- - -

Subtract equation (4) from equation (3),

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Page 7: Simultaneous equations

โˆด ๐“ =

= โ€ฆ(5)

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Page 8: Simultaneous equations

โˆดy =

= โ€ฆ(6)

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Page 9: Simultaneous equations

D =

=

=

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Page 10: Simultaneous equations

From equations (5) and (6)

Determinants we get, ๐“ = and y =

This method of obtaining solution of simultaneous equations by using determinants

is known as Cramerโ€™s Rule.

Page 11: Simultaneous equations

Solve the following simultaneous equations using Cramerโ€™s rule.

The given equations are 5 โ€“y = 5๐“5 + y = 15๐“

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Page 12: Simultaneous equations

D = = 5 ร— 1 โ€“ (-1 ร— 5) = 5+ 5 = 10

= = 5 ร— 1 โ€“ (-1 ร— 15) = 5 + 15 = 20

= =5 ร— 15 โ€“ (5 ร— 5) = 75 โ€“ 25 = 50

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Page 13: Simultaneous equations

๐“ = = = 10

y = = = 5

โˆด ๐“ = 10 and y = 5 is the solution of the given simultaneous equations.