The solution of the system x + y – 3z = – 6, -7y + 7z = 7, 3z = 9

1.	The solution of the system x + y – 3z = – 6, -7y + 7z = 7, 3z = 9 is …(1) x = 1, y = 2, z = 3 (2) x = -1, y = 2, z = 3 (3) x = -1, y = -2, z = 3 (4) x = 1, y = 2, z = 3
Answer» (1) x = 1, y = 2, z = 3 x + y – 3x = – 6 …(1) – 7y + 7z = 7 ...(2) 3z = 9 ...(3) From (3) we get z = 9/3 = 3 Substitute the value of z in (2) -7y + 7(3) = 7 -7y = -14 Substitute the value of y = 2 and z = 3 in (1) x + 2 – 3(3) = -6 x + 2 – 9 = -6 x = -6 + 7 x = 1 The value of x = 1, y = 2 and z = 3

The solution of the system x + y – 3z = – 6, -7y + 7z = 7, 3z = 9 is …(1) x = 1, y = 2, z = 3 (2) x = -1, y = 2, z = 3 (3) x = -1, y = -2, z = 3 (4) x = 1, y = 2, z = 3

Answer»

(1) x = 1, y = 2, z = 3

x + y – 3x = – 6 …(1)

– 7y + 7z = 7 ...(2)

3z = 9 ...(3)

From (3) we get

z = 9/3 = 3

Substitute the value of z in (2)

-7y + 7(3) = 7

-7y = -14

Substitute the value of y = 2 and z = 3 in (1)

x + 2 – 3(3) = -6

x + 2 – 9 = -6

x = -6 + 7

x = 1

The value of x = 1, y = 2 and z = 3