Ask Question
27 December, 20:10

Solve the system by substitution

-x-y-z=-8

-4x+4y+5z=7

2x+2x=4

+2
Answers (1)
  1. 27 December, 22:27
    0
    Let

    -x - y - z = - 8 ... (1a)

    -4x + 4y + 5z = 7 ... (2a)

    2x + 2x = 4 ... (3a)

    since (3a) a is an equation solely in x make x the subject of the equation

    2 (x + x) = 4

    divide both sides by 2

    (x + x) = 2

    2x = 2

    x = 1 ... (3b)

    substitute x in (3b) for x in (1a)

    - (1) - y - z = - 8

    make y the subject of the equation

    -y - z = - 8 + 1

    -y = - 7 + z

    y = 7 - z ... (1b)

    substitute y in (1b) for y in (2a) as well as the value of x (x = 1)

    -4 (1) + 4 (7 - z) + 5z = 7

    - 4 + 28 - 4z + 5z = 7

    -24 + z = 7

    z = 7 + 24

    z = 31

    By using (1a) solve for y

    - (1) - y - (31) = - 8

    -1 - y - 31 = - 8

    y = - 1 - 31 + 8

    y = - 24

    ∴ the solutions of the system are x = 1; y = - 24; z = 31
Know the Answer?
Not Sure About the Answer?
Get an answer to your question ✅ “Solve the system by substitution -x-y-z=-8 -4x+4y+5z=7 2x+2x=4 ...” 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