Question

Solve for X

3x + 2y + z = 6
x + y + 3z = –5
4x + y – z = 10

Answer 1

\[(3x + 2y + z) + (4x + y - z) = 16 => 7x + 3y = 16 \]
Multiply the third equation by 3, then add to the second, we'll get a new equation. Using it and what we got above to solve for x and y. Then find z.

Answer 2

12x+3y-3z=30

Answer 3

@cwrw238

Answer 4

x + y + 3z = –5
12x+3y-3z=30 add these 2 equations
13x + 4y = 25
7x + 3y = 16 - the equation from tvcong

Answer 5

now multiply ist equation by -3 and 2nd by 4
-39x - 12y = -75
28x + 12y = 64
adding:
-11x - -11
x = 1

plug x = 1 into 7x + 3y = 16:

7 + 3y = 16
3y = 9

y = 3

now plug x = 1 and y = 3 into one of the original equations to find z