Question

Resolva o sistema, utilizando a regra de Cramer:
x + y + 2z = -1
4x + y + 4z= -2
2x - y + 2z = -4

Answer 1

D = 1...1...2
.......4...1...4
.......2..-1...2

D = 
2+8-8-4-8-4
D = 2-16
D = -14

Dx:
1...2..-1
1...4..-2
-1..2..-4
Dx = 
-16-2+4-4+8+4 
Dx = -18+12
Dx = -6

Dy:
1...2..-1
4...4..-2
2...2..-4

Dy =
-16+8-8+8+32+4
Dy = -16+8+32+4
Dy = 44-16
Dy = 28

Dz:
1...1..-1
4...1..-2
2..-1..-4

Dz = 
-4-4+4+2+16-2
Dz = 22

x = Dx/D --> x = -6/-14 --> x = 3/7
y = Dy/D --> y = 28/-14 --> y = -2
z = Dz/D --> z = 22/-14 --> z = 11/-7