SIMULTANEOUS EQUATIONS 2

Solve the following equations by substitution method.

2x - 3y = 10

x + 5y = 18

Solution

2x - 3y = 10 ----------- (i)

x + 5y = 18 ---------- (ii)

From equation (ii)

x + 5y = 18

x = 18- 5y ----------(iii)

Substitute equation (iii) in (i) above,

2x - 3y = 10

2(18- 5y) - 3y = 10

36 – 10y – 3y = 10

36 – 13y = 10

– 13y = 10 - 36

– 13y =  - 26

– 13y =  - 26

  -13        -13

y = 2

From equation (iii)

x = 18 - 5y

x = 18 - 5(2)

x = 18 - 10

x = 8

Hence x = 8 and y = 2.

TRY THIS…………….

Solve the following equations by substitution method.

5x - 6y = 20

x + y = 15