Answers

2014-12-02T21:14:04+08:00
Let 'x' be one of the numbers
      'y' be the other number
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-the sum of two numbers is 15 
x + y = 15     -----equation 1
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-three times one of the number is 19 less than 5 times the other
3y = 5x - 19       -------equation 2
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From equation 1
x + y = 15
x = 15 - y    ---equation 1'
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Substitute equation 1' to equation 2
3y = 5x - 19
3y = 5(15-y) - 19
3y = 75 - 5y - 19
Transpose -5y to the left side of the equation
3y + 5y = 75 - 19
8y = 56
y = 7
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Substitute y=7 to equation 1'
x = 15 - y
x = 15 - 7
x = 8
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Therefore the two numbers are 7 and 8.


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