Algebra

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I need help solving this set of equations by substitution.


xy=2
3x − y + 5 = 0

I originally used (3x+5=y) and came up with (x=.333 and x=-2) but when I substitute it into the original equation I get (y=2 and y=1) and it is wrong according to my homework. Please help me!

  • Algebra -

    ok, go with y = 3x+5

    into the 1st
    x(3x+5) = 2
    3x^2 + 5x - 2 = 0
    ((3x-1)(x+2) = 0
    x = 1/3 or x = -2 --- > you are correct

    if x = 1/3, y= 3(1/3) + 5 = 6
    if x = -2 , y = 3(-2) + 5 = -1

    so x=1/3, y=6 OR x=-2, y =-1

    I don't know how you got your values ???

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