Resposta :
x - 2y - 2z = -1 .... (i)
x - 2z = 3 ............ (ii)
y - z = 1 ............. (iii)
De (ii) → x = 2z + 3
De (iii) → y = z +1
x - 2y - 2z = (2z+3) - 2(z+1) - 2z = 2z + 3 - 2z - 2 - 2z = 1 - 2z
1 - 2z = -1
1 + 1 = 2z
2z = 2
z = 2/2
z = 1
x = 2z + 3 = 2.1 + 3 = 2 + 3 = 5
y = z + 1 = 1 + 1 = 2
z = 1
Logo:
x = 5, y = 2 e z = 1.
x - 2z = 3 ............ (ii)
y - z = 1 ............. (iii)
De (ii) → x = 2z + 3
De (iii) → y = z +1
x - 2y - 2z = (2z+3) - 2(z+1) - 2z = 2z + 3 - 2z - 2 - 2z = 1 - 2z
1 - 2z = -1
1 + 1 = 2z
2z = 2
z = 2/2
z = 1
x = 2z + 3 = 2.1 + 3 = 2 + 3 = 5
y = z + 1 = 1 + 1 = 2
z = 1
Logo:
x = 5, y = 2 e z = 1.