SIMULTANEOUS EQUATIONS 1

Solve the following equations by substitution method.

2x - 3y = 4

x + 5y = 15

Solution

2x - 3y = 4 ----------- (i)

x + 5y = 15 ---------- (ii)

from equation (ii)

x + 5y = 17

x = 15- 5y ----------(iii)

Substitute equation (iii) in (i) above,

2x - 3y = 4

2(15- 5y) - 3y = 4

30 – 10y – 3y = 4

30 – 13y = 4

– 13y = 4 - 30

– 13y =  - 26

– 13y =  - 26

  -13        -13

y = 2

From equation (iii)

x = 15- 5y

x = 15- 5(2)

x = 15- 10

x = 5

Hence x=5 and y=2.

TRY THIS…………….

Solve the following equations by substitution method.

      5x - 6y = 20

      x - 3y = -5