Answer:
Explanation:
The system of equations given are:
5x - y + z = -6 ------------- i
2x + 7y + 3z = 8 ---------- ii
x + 2z = 6 ----------------- iii
Let us deal with equation i and ii first since they have 3 variables x, y and z;
5x - y + z = -6 x 7
2x + 7y + 3z = 8 x 1
35x - 7y + 7z = -42 ---- iv
2x + 7y + 3z = 8 ---- v
Add equation iv and v;
37x + 10z = -34 ------vi
So, let us solve equation vi and iii:
x + 2z = 6 - ---------- iii x 10
37x + 10z = -34 --- iv x 2
10x + 20z = 60 vi
74x + 20z = -68 vii
Subtract vi - vii;
-64x = 128
x = -2
So; put x = -2 into iii;
x + 2z = 6
-2 + 2z = 6
2z = 6 + 2 = 8
z = 4
Put x = -2 and z = 4 into equation i;
5(-2) - y + 4 = - 6
-10 -y +4 = -6
-6 - y = -6
-y = 0
y = 0