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On line solution of multivariate equations：
    First set the elements of the equation (i.e. the number of unknowns), then click the "Next" button to enter the coefficients of each element of the equation set, and click the "Next" button to obtain the solution of the equation set.
    Note that the coefficients of each element of the equation system can only be numbers, not algebraic expressions (including mathematical functions).
    Current location：Equations > Multivariate equations > Answer
detailed information：
The input equation set is:
 7x + 2y + 9z = 4    (1)
 8x + 4y + 5z = 7    (2)
 6x + 7y + 2z = 9    (3)
Question solving process:

Multiply both sides of equation (1) by 8
Divide the two sides of equation (1) by 7, the equation can be obtained:
         8x + 
16
7
y + 
72
7
z = 
32
7
    (4)
, then subtract both sides of equation (4) from both sides of equation (2), the equations are reduced to:
 7x + 2y + 9z = 4    (1)
 
12
7
y - 
37
7
z = 
17
7
    (2)
 6x + 7y + 2z = 9    (3)

Multiply both sides of equation (1) by 6
Divide the two sides of equation (1) by 7, the equation can be obtained:
         6x + 
12
7
y + 
54
7
z = 
24
7
    (5)
, then subtract both sides of equation (5) from both sides of equation (3), the equations are reduced to:
 7x + 2y + 9z = 4    (1)
 
12
7
y - 
37
7
z = 
17
7
    (2)
 
37
7
y - 
40
7
z = 
39
7
    (3)

Multiply both sides of equation (2) by 37
Divide the two sides of equation (2) by 12, the equation can be obtained:
         
37
7
y - 
1369
84
z = 
629
84
    (6)
, then subtract both sides of equation (6) from both sides of equation (3), the equations are reduced to:
 7x + 2y + 9z = 4    (1)
 
12
7
y - 
37
7
z = 
17
7
    (2)
 
127
12
z = - 
23
12
    (3)

Multiply both sides of equation (3) by 444
Divide both sides of equation (3) by 889, get the equation：
         
4699
889
z = - 
851
889
    (7)
, then add the two sides of equation (7) to both sides of equation (2), get the equation：
 7x + 2y + 9z = 4    (1)
 
12
7
y = 
1308
889
    (2)
 
127
12
z = - 
23
12
    (3)

Multiply both sides of equation (3) by 108
Divide both sides of equation (3) by 127, get the equation：
         
1143
127
z = - 
207
127
    (8)
, then subtract both sides of equation (8) from both sides of equation (1), get the equation：
 7x + 2y = 
715
127
    (1)
 
12
7
y = 
1308
889
    (2)
 
127
12
z = - 
23
12
    (3)

Multiply both sides of equation (2) by 7
Divide both sides of equation (2) by 6, get the equation：
         2y = 
218
127
    (9)
, then subtract both sides of equation (9) from both sides of equation (1), get the equation：
 7x = 
497
127
    (1)
 
12
7
y = 
1308
889
    (2)
 z = - 
23
127
    (3)

The coefficient of the unknown number is reduced to 1, and the equations are reduced to：
 x = 
71
127
    (1)
 y = 
109
127
    (2)
 z = - 
23
127
    (3)


Therefore, the solution of the equation set is:
x = 
71
127
y = 
109
127
z = - 
23
127


Convert the solution of the equation set to decimals:
x = 0.559055
y = 0.858268
z = -0.181102

解方程组的详细方法请参阅：《多元一次方程组的解法》
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