27500y = 16500+ 1600 x+4000 z
30000z= 15000+400x+5000y
Solution: Move the unknown to the left and the constant to the right, and divide the left and right sides by 100 to get:
30x-25y- 10z=75
16x-275y+40z=- 165
4x+50y-300z=- 150
Obtained from the first formula
25y=30x- 10z-75
Substitute the second and third equations to get the equation:
16x- 1 1(30x- 10z-75)+40z+ 165 = 0
4x+2(30x- 10z-75)-300 z+ 150 = 0
Simplify to get:
-3 14x+ 150z+990=0
64x-320z=0
This is easy to understand:
According to the second equation:
X=5z, substitute the first one to get:
-3 14x+30x+990=0
284x=990
Solution:
x=495/ 142,
Then substitute x=5z to get it.
z=99/ 142,
Substitute x and z into 25y=30x- 10z-75.
y=32 1/355