Ask Question
26 July, 08:51

Systems of equations using substitution 3 x+4 y=-31 x+y=6

+3
Answers (2)
  1. 26 July, 10:24
    0
    3x + 4y = - 31

    x + y = 6

    Rewrite the second one (because it's more convenient) : y = 6-x

    Replace in the first equation: 3x + 4 (6-x) = - 31

    Simplify: 3x + 24 - 4x = - 31

    Simplify: - 1x + 24 = - 31

    Subtract: - 1x = - 31 - 24

    Simplify:-1x = - 55 or x=55

    Plug into the first equation: 55+y=6

    Subtract: y=6-55 or y = - 49

    Answer: x=55, y=-49

    Verify:

    x+y = 6

    55-49=6? True

    3x + 4y = - 31

    3 (55) + 4 (-49) = - 31?

    165-196=-31? True
  2. 26 July, 11:37
    0
    3x+4y=-31

    x+y=6

    multiply second equation by - 3

    -3x-3y=-18

    add to first equation

    3x+4y=-31

    -3x-3y=-18 +

    0x+y=-49

    y=-49

    subsitute

    x+y=6

    x-49=6

    add 49 to both sides

    x=55

    the solution is (x, y) form is

    (55,-49)
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “Systems of equations using substitution 3 x+4 y=-31 x+y=6 ...” in 📙 Mathematics if there is no answer or all answers are wrong, use a search bar and try to find the answer among similar questions.
Search for Other Answers