Anonymous
Anonymous asked in Science & MathematicsMathematics · 3 weeks ago

Solve each system using substitution?

-7x+2y=18

6x+6y=0

5 Answers

Relevance
  • 3 weeks ago
    Best Answer

    {-7x+2y=18 ⇒ 2y=18+7x

    {6x+6y=0 divide both sides by 3. 2x+2y=0

    Substitute 2y from the first to the second

    2x+(18+7x)=0

    9x+18=0

    9x=-18

    x=-2

    Put it into the second

    6(-2)+6y=0 divide both sides by 6

    -2+y=0

    y=2

    The unique solution is x=-2 & y=2

  • 3 weeks ago

    [-7x+2y=18 ]3

    6x+6y=0

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

    -21x + 6y = 54

    -[6x + 6y = 0]

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

    ... - 27x = 54

    x = -2 answer//

    plug in x = - 2 to eq 2

    6x+6y=0

    6(-2) + 6y = 0

    - 12 + 6y = 0

    6y = 12

    y = 2 answer//

  • David
    Lv 7
    3 weeks ago

    Solving the given simultaneous equations x = -2 and y = 2

  • 3 weeks ago

    -7x + 2y = 18 

    6x + 6y = 0

    2x + 2y = 0

    -9x = 18

    x = -2, y = 2

  • How do you think about the answers? You can sign in to vote the answer.
  • 3 weeks ago

    6x+6y=0 means y = -x, so substitute y for -x in -7x+2y=18

    9y=18, so y = 2 and x = -2

Still have questions? Get your answers by asking now.