Answer:
(x, y, z) = (-4, -5, 2)
Step-by-step explanation:
You want the solution to the 3×3 system of equations ...
- 3x -y -4z = -15
- -4x -4y -z = 34
- 2x +3y +5z = -13
Tools
There are many tools available for solving a system of equations. A typical hand-held graphing calculator offers at least two methods. An online graphing calculator solution is shown in the attachment.
For the attached solution, we defined z in terms of x and y using the second equation. This effectively reduces the system to a 2×2 system, which is easily solved. The same "substitution" method can be used when solving the system by hand.
The graph shows the solution to be (x, y, z) = (-4, -5, 2).
Manual solution
Using z = -4x -4y -34 from the second equation, the system reduces to ...
3x -y -4(-4x -4y -34) = -15
19x +15y = -151
and
2x +3y +5(-4x -4y -34) = -13
-18x -17y = 157
Writing these equations in general form, we have ...
- 19x +15y +151 = 0
- 18x +17y +157 = 0
The "cross multiplication method" gives the solution for x and y as ...
D = (19)(17) -(18)(15) = 53
x = (15(157) -17(151))/D = -212/53 = -4
y = (151(18) -157(19))/D = -265/53 = -5
Then z is ...
z = -4(-4) -4(-5) -34 = 16 +20 -34 = 2
The solution is (x, y, z) = (-4, -5, 2).
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You can read more about the cross multiplication method here.
https://brainly.com/question/26397343
