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Help with system of equations!!!?

+1 vote
I need help solving this system of equations:

D+Q=15
.10D+.25Q=2.85
asked Jan 11, 2013 in ALGEBRA 1 by abstain12 Apprentice

1 Answer

+2 votes
D+Q=15-------------1

.10D+.25Q=2.85------------2

multiply by 10 equation 2.

        D+Q=15-------------3

  (-)   D + 2.5Q =28.5-----------4

   --------------------------------

            - 1.5 Q= - 13.5

   divide by - 1.5 in the euation

                  Q = -13.5 / - 1.5

                  Q = 9

substitute Q=9 in the equatin 1

   D + 9 = 15

subtract 9 from each side

  D + 9 - 9 = 15 -  9

            D = 6

the solution is (D ,Q ) = ( 6 ,9 )
answered Jan 11, 2013 by krish Pupil

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