Question

Solve the system using an algebraic approach
3x + 4y + z = 24
5x - 5y - z = 4
5x + y + 4z = 8

Answer 1

one guy just asked the same problem!

Answer 2

3x + 4y + z = 24
5x - 5y - z = 4
----------------add
8x - y = 28

5x - 5y - z = 4 -->(4)
5x + y + 4z = 8
-------------
20x - 20y - 4z = 16 (result of multiplying by 4)
5x + y + 4z = 8
------------add
25x - 19y = 24

8x - y = 28 --->(-19)
25x - 19y = 24
--------------
-152x + 19y = - 532 (result of multiplying by -19)
25x - 19y = 24
-------------add
- 127x = - 508
x = -508/-127
x = 4

8x - y = 28
8(4) - y = 28
32 - y = 28
32 - 28 = y
4 = y

5x - 5y - z = 4
5(4) - 5(4) - z = 4
20 - 20 - z = 4
-z = 4
z = -4

check..
3x + 4y + z = 24
3(4) + 4(4) - 4 = 24
12 + 16 - 4 = 24
28 - 4 = 24
24 = 24 (correct)

solution is : x = 4, y = 4, and z = -4

Answer 3

Thank you!

Answer 4

your welcome....elimination is not really that hard, just time-consuming