SIMULTANEOUS EQUATIONS A2

Solve the following equations by substitution method.

4x - 2y = 6

x + y = 9

solution

4x - 2y = 6----------- (i)

x + y = 9---------- (ii)

from equation (ii)

x + y = 9

x = 9- y ----------(iii)

substitute equation (iii) in (i) above,

4x - 2y = 6

4(9- y) - 2y = 6

36- 4y - 2y = 6

36- 6y = 6

36- 6 = 6y

30 = 6y

30 = 6y

  6     6

5 = y

From equation (iii)

x = 9- y ----------(iii)

x = 9- 5

 x = 4

Hence x=4 and y=5.