31. what is the solution to the system of equations? -7x-2y+z=-2 6x-y-z=-18 5x+4y-z=18

x = -1, y = 7, z = 5

use 2. - 3.

= -1 -5 0 -36 --- 4.

use 1. + 2.

= -1 -3 0 -20 --- 5.

use 4. + 5.

= 0 -8 0 -56

=> y = 7

y = 7 back into 5.:

x - 35 = -36

=> x = -1

x = -1 and y = 7 back into 1.:

7 - 14 + z = -2

=> z = 5

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so:

its totaly b

your welcome btw