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Question:

amreen25
amreen25
Student

Solve the following equations for the two unknowns (simultaneously):

(i) 2p+5q =6 and q-p=4

(ii) -3(g+2c)= -27 and 8g-12c=44

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Posted by amreen25 on Thursday October 1, 2009 at 12:21 PM and tagged with algebra, math, mathematics, simultaneous equations.

Answers:

  1. kjcdb8er
    kjcdb8er Teacher

    eNotes Editor

    You can add equations together just like you can add numbers together. Lets do that to eliminate one of the variables and solve both these problems.

    1) 2p + 5q = 6

    -p + q = 4                 Multiply this equation by 2, and add it to the first equation.

    2p + 5q - 2p + 2q = 6 + 8

    7q = 14 --> q = 2

    Now finding p is easy because p = q - 4 = 2 - 4 = -2

    ii) Do the same for the second equation:

    -3g - 6c = -27             Multiply this equation by -2, and add to the next equation.

    8g - 12c = 44

    6g + 12c + 8g - 12c = 54 + 44

    14g = 98  --> g = 7

    Plug g back in to find c = 1

    Rate answer:

    Posted by kjcdb8er on Thursday October 1, 2009 at 1:25 PM