6.4.7 Linear Equations, PT3 Focus Practice



Question 19:
Calculate the value of x and of that satisfy the following simultaneous linear equations:
  x + 6 y = 12 2 3 x + 2 y = 6
[4 marks]
Solution:
x + 6 y = 12 x = 12 6 y ( 1 ) 2 3 x + 2 y = 6 ( × 3 ) 2 x + 6 y = 18 ( ÷ 2 ) x + 3 y = 9 ( 2 )
 
Substitute (1) into (2),
12 – 6y + 3= 9
–3y = –3
= 1
Substitute y = 1 into (1),
x = 12 – 6 (1)
x = 6 

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