Friday 20 December 2013

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.

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