Answer:
x=1
y=−2
z=5
(heres how i got the answer)
Explanation:
x+2y+3z=12
x−3y+4z=27
−x+y+2z=7
Solve x+2y+3z=12 for x.
x=−2y−3z+12
Substitute −2y−3z+12 for x in the second and third equation.
−2y−3z+12−3y+4z=27
−(−2y−3z+12)+y+2z=7
Solve equations for y and z respectively.
y=−3+ 
5
1
 z
z= 
5
19
 − 
5
3
 y
Substitute −3+ 
5
1
 z for y in the equation z= 
5
19
 − 
5
3
 y.
z= 
5
19
 − 
5
3
 (−3+ 
5
1
 z)
Solve z= 
5
19
 − 
5
3
 (−3+ 
5
1
 z) for z.
z=5
Substitute 5 for z in the equation y=−3+ 
5
1
 z.
y=−3+ 
5
1
 ×5
Calculate y from y=−3+ 
5
1
 ×5.
y=−2
Substitute −2 for y and 5 for z in the equation x=−2y−3z+12.
x=−2(−2)−3×5+12
Calculate x from x=−2(−2)−3×5+12.
x=1
The system is now solved.
x=1
y=−2
z=5