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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:
 9x -6y = 11    (1)
-6x + 15y + 21z = 0    (2)
-18x -18y + z = 0    (3)
Question solving process:

Multiply both sides of equation (1) by 2
Divide the two sides of equation (1) by 3, the equation can be obtained:
         6x -4y = 
22
3
    (4)
, then add the two sides of equation (4) to both sides of equation (2), the equations are reduced to:
 9x -6y = 11    (1)
 11y + 21z = 
22
3
    (2)
-18x -18y + z = 0    (3)

Multiply both sides of equation (1) by 2, the equation can be obtained:
         18x -12y = 22    (5)
, then add the two sides of equation (5) to both sides of equation (3), the equations are reduced to:
 9x -6y = 11    (1)
 11y + 21z = 
22
3
    (2)
-30y + z = 22    (3)

Multiply both sides of equation (2) by 30
Divide the two sides of equation (2) by 11, the equation can be obtained:
         30y + 
630
11
z = 20    (6)
, then add the two sides of equation (6) to both sides of equation (3), the equations are reduced to:
 9x -6y = 11    (1)
 11y + 21z = 
22
3
    (2)
 
641
11
z = 42    (3)

Multiply both sides of equation (3) by 231
Divide both sides of equation (3) by 641, get the equation：
         
13461
641
z = 
9702
641
    (7)
, then subtract both sides of equation (7) from both sides of equation (2), get the equation：
 9x -6y = 11    (1)
 11y = - 
15004
1923
    (2)
 
641
11
z = 42    (3)

Multiply both sides of equation (2) by 6
Divide both sides of equation (2) by 11, get the equation：
         6y = - 
2728
641
    (8)
, then add the two sides of equation (8) to both sides of equation (1), get the equation：
 9x = 
4323
641
    (1)
 11y = - 
15004
1923
    (2)
 z = 
462
641
    (3)

The coefficient of the unknown number is reduced to 1, and the equations are reduced to：
 x = 
1441
1923
    (1)
 y = - 
1364
1923
    (2)
 z = 
462
641
    (3)


Therefore, the solution of the equation set is:
x = 
1441
1923
y = - 
1364
1923
z = 
462
641


Convert the solution of the equation set to decimals:
x = 0.749350
y = -0.709308
z = 0.720749

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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