To answer this item, we express the y in the first equation in terms of the other variables. This is, y = 7 + z - 2x Then, substitute the y's in the second and third equation with that of the expression derived in the first equation.
(2) -x - 2(7 + z - 2x) + 4z = -15
Simplifying, -x - 14 -2z + 4x + 4z = -15
Simplifying further, 3x + 2z = -1
(3) x + 2(7 + z - 2x) - 5x = 17
Simplifying, x + 14 + 2z - 4x - 5x = 17
Simplifying further, -3x - 3z = 3
The equations derived are, 3x + 2z = -1 x + z = -1
The values of x and z in the equation are 1 and -2, respectively. To solve for y,
