Explanation:
I assume we have to find the solution of this system of equations.
2x-6y+9z=-8
5x+y+2z=10
3x+y-8z = -28
let's subtract the third from the second equation to get rid of y :
5x + y + 2z = 10
- 3x + y - 8z = -28
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2x + 0 + 10z = 38
2x + 10z = 38
x + 5z = 19
x = 19 - 5z
next, let's multiply the 3rd equation by 6 and add it to the first equation :
2x - 6y + 9z = - 8
18x + 6y - 48z = -168
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20x 0 - 39z = -176
now, we use
x = 19 - 5z in
20x - 39z = -176
20(19 - 5z) - 39z = -176
380 - 100z - 39z = -176
556 - 139z = 0
556 = 139z
z = 556/139 = 4
x = 19 - 5z = 19 - 5×4 = 19 - 20 = -1
now we use one of the original squadrons to get y.
e.g.
5×-1 + y + 2×4 = 10
-5 + y + 8 = 10
3 + y = 10
y = 7
x = -1
y = 7
z = 4