Question

No sistema :
1x + 1y + 0z = 4
2x - 0y - 1z = -2
0x + 1y + 1z = 7

Calcule o valor de : 2x-y+2-z

Answer 1

x + y = 4 --> x = 4 - y
2x - z = -2
y + z = 7 --> z = 7 - y

2(4 - y) - (7 - y) = -2
8 - 2y - 7 + y = -2
-y + 1 = -2
-y = -3
y = 3

z = 7 - y
z = 7 - 3
z = 4

x = 4 - y
x = 4 - 3
x = 1


2x - y + 2 - z =
2(1) - 3 + 2 - 4 =
2 - 3 + 2 - 4 =
-3