5x+6x-2 1+2z=2 Merge: 1 1x+2z=23.

3x-4z=4 is converted into: z=3/4x- 1, and substituted into 1 1x+2z=23.

Get:

1 1x+ 1.5x-2 = 23

The solution is x=2.

Substitute y=2x-7.

The solution is y=-3.

X=2 becomes 3x-4z=4.

The solution is z=0.5.

4x+9y= 12........( 1)

3y-2z= 1........(2)

7x+5z= 19/4.....(3)

( 1)-3*(2):4x+6z=9...........(4)

(4)*7-(3)*4: 22z=44

z=2

Substitution (4):4x+6*2=9.

4x=-3

x=-3/4

Substitute z=2 into (2):3y-2*2= 1.

y=5/3

The solution is:

x=-3/4

y=5/3

z=2

(1) solution:

4x-9z = 17……A

3x+y+ 15z = 18……B

x+2y+3z = 2……C

B*2-C:5x+27z=34……D

If A and D are connected together, X = 5, Y = 1/3 and Z =-2 can be deduced.

(2) Solution:

2x+4y+3z=9，( 1)

3x-2y+5z= 1 1，(2)

5x-6y+7z= 13，(3)

(2)*2, get

6x-4y+ 10z=22，(4)

(2)*3, get

9x-6y+ 15z=33，(5)

The same is true of (1)+(4)

8x+ 13z=3 1，(6)

The same is true of (5)-(3)

4x+8z=20，(7)

(7)*2, get

8x+ 16z=40，(8)

The same is true of (6)-(8)

-3z=-9，

So z=3,

Substitute z=3 into (7) and you get

x=- 1，

Substituting x =- 1 and z = 3 into (1), we get

y= 1/2，

So the solution of the original equation is

x=- 1，

y= 1/2，

z=3。

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