KAEDAH PENGHAPUSAN PERSAMAAN SERENTAK

1.2 SIMULTANEOUS EQUATIONS

Sometimes we need to find the solutions of a pair of equations. There are
many problems can be solved by using two equations in two unknowns
and solving them simultaneously. There are many methods to solve these
equations but in this unit we only focus to two methods, namely:

i. Substitution Method
ii. Elimination Method
ELIMINATION METHOD

Make the coefficients for one of the variables numerically equal.
Eliminate one variable by addition or subtraction

Solve the equation for the value of one variable, then the other.

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Example 1.4 :

Use the elimination method to solve the following pairs of

simultaneous equations.
3m – 4n = 10
3m – 2n = 8

Solution: 3m – 4n = 10 ------- (1)
(1) – (2) : 3m – 2n =
8 ------- (2) Since the coefficients of m
-2n =
n are the same, subtracting
=
2 the two equations will

=2 eliminate m.
−2

-1

Substitute n = -1 into equation (2) :
3m – 2(-1) = 8

3m + 2 = 8

3m = 8 – 2

3m = 6

m= 6
3

=2

Hence, the solution is m = 2 and n = -1.

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