Question

Solve for z? 2x-4y+4z-6w=4 6w-4x+4y-4z=-12 6w+4x-2y+6z=64 4z+2w+6y-4x=56

Answer 1

Answer:

z ≈ 9.22

Step-by-step explanation:

Given the equations

2x-4y+4z-6w=4 ................ 1

6w-4x+4y-4z=-12 ...............2

6w+4x-2y+6z=64 ............... 3

4z+2w+6y-4x=56 ................ 4

We will first need to reduce the equation by cancelling out some variables.

Add equations 1 and 2 will give;

(2x-4x)+(-4y+4y)+(4z-4z)+ (-6w+6w) = 4+12

-2x +0 = 16

-2x = 16

x = -8

Also, equation 2 minus 3

6w-6w+(-4x-4x)+4y+2y+(-4z-6z) = 12-64

-8x+6y-10z = -52

-8(-8)+6y-10z = -52

64+6y-10z = -52

6y-10z  = -52-64

6y-10z = -116

3y-5z = -58 ... 5

Equation 3 * 1 and eqn 4 * 3

6w+4x-2y+6z=64 ............... 3

4z+2w+6y-4x=56 ................ 4

6w+4x-2y+6z=64

12z+6w+18y-12x= 168

Subtracting both equations;

16x-20y-6z = -104

8x-10y-3z = -52

8(-8)-10y-3z = -52

-64-10y-3z = -52

-10y-3z = -52+64

-10y-3z = 12 ....... 6

equating 5 and 6 and solving simultaneously;

3y-5z = -58 ... 5 * 10

-10y-3z = 12 ....... 6 * 3

30y-50z = -580

-30y-9z = 36

Add both equations

-50z-9z = -580+36

-59z = -544

z = -544/-59

z = 9.22

Hence z ≈ 9.22