Page 98 - Mathematics_F1

Solving linear simultaneous equations numbers so as to make the
There are several methods of solving coefficients of the chosen
simultaneous equations. This section variable in both equations
discusses how solutions of linear equal.
simultaneous equations are obtained Step 2: Add the new equations if the
FOR ONLINE READING ONLY
by elimination and substitution methods. coefficients of the chosen Tanzania Institute of Education
variable to be eliminated are
Solving linear simultaneous equations opposite in signs, otherwise
by elimination method subtract them.

Elimination method involves performing Step 3: Solve the obtained equations.
suitable mathematical operations to This gives the value of one
reduce the two equations into a single of the unknowns.
equation with one unknown. The Step 4: Repeat steps 1 to 3 for the
following are the steps for solving linear value of the second unknown.
simultaneous equations by elimination
method: Note: Some simultaneous equations
Step 1: Choose the easiest variable to can be converted into linear
be eliminated. Multiply the equations by changing the
given equations by suitable variables.

Example 5.30

Solve the following linear simultaneous equations by elimination method:

 6x += 15
y
 3x y 9
+=

Solution
Label the equations with numbers, say (1) and (2);

 6x y 15 (1)
+=

+=
 3x y 9 (2)
Choose a variable to be eliminated, say x:
Eliminate x to get y: Mathematics Form One

The coefficent of in (1) is 6x  without considering their signs
The coefficent of in (2) is 3x 


91

25/09/2025 15:01:11
Mathematics form 1.indd 91 25/09/2025 15:01:11
Mathematics form 1.indd 91