If x + y = 12 and 3x - y = 20, find the value of 2x - y

  • A 8
  • B 10
  • C 12
  • D 15
waec 2006mathematics

The correct answer is C. 12

x + y = 12

+ 3x - y = 20

---------------

4x = 32

x = 8

x + y = 12; 8 + y = 12; y = 12 - 8

= 4

2x - y = 2(8) - 4; 16 - 4 = 12

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