SIMULTANEOUS EQUATIONS A1

Solve the following equations by substitution method.

2x - 3y = 8

x + 5y = 17

solution

2x - 3y = 8 ----------- (i)

x + 5y = 17 ---------- (ii)

from equation (ii)

x + 5y = 17

x = 17- 5y ----------(iii)

substitute equation (iii) in (i) above,

2x - 3y = 8

2(17- 5y) - 3y = 8

34 – 10y – 3y = 8

34 – 13y = 8

– 13y = 8 - 34

– 13y =  - 26

– 13y =  - 26

  -13        -13

y = 2

From equation (iii)

x = 17- 5y

x = 17- 5(2)

x = 17- 10

 x = 7

Hence x=7 and y=2.