Elimination Method

This method is very useful to solve simultaneous equations especially when none of the coefficients of the unknown is 1. To eliminate means to get rid of a variable.

Example 2.1.1:

6x + 5y = 15 
3x + 5y = 12 

Solution

Since the coefficients of y in both equations are the same, the y-variable can be eliminated by subtracting equation (2) from (1)

	6x	+5y	=	15 …………(1)
–	3x	+5y	=	12 …………(2)
	3x		=	3

This can be simply calculated as;

\( \scriptsize (6x \: – \: 3x) + (5y \: – \: 5y) = 15 \: -\: 12 \)

\( \scriptsize 3x + 0 = 3 \)