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  • 22-07-2015
  • Mathematics
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The difference of two numbers, a and b, is 21. The difference of 5 times a and two times b is 18. What are the values of a and b

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konrad509
konrad509 konrad509
  • 22-07-2015
[tex]a-b=21 |\cdot(-2)\\ 5a-2b=18\\\\ -2a+2b=-42\\ \underline{5a-2b=18}\\ 3a=-24\\ a=-8\\\\ -8-b=21\\ b=-29 [/tex]
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naǫ
naǫ naǫ
  • 22-07-2015
[tex]a-b=21 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\times (-2) \\ 5a-2b=18 \\ \\ -2a+2b=-42 \\ \underline{5a-2b=18 \ \ \ \ \ \ \ } \\ 5a-2a=18-42 \\ 3a=-24 \\ a=\frac{-24}{3} \\ a=-8 \\ \\ a-b=21 \\ -8-b=21 \\ -b=21+8 \\ -b=29 \\ b=-29[/tex]

a=-8 and b=-29.
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