Examine consistency. Solve if possible.
x1 + x2 + x3 = -3,
3x1 + x2 – 2x3 = -2,
2x1 + 4x2 + 7x3 = 7
Soln:
We have,
Or, x1 + x2 + x3 = -3 …(i)
Or, 3x1 + x2 – 2x3 = -2 …(ii)
Or, 2x1 + 4x2 + 7x3 = 7 …(iii)
Multiplying equation (I) by 3 and subtracting (ii) from (i),
Or, 2x2 + 5x3 = 7 ….(iv)
Multiplying equation (i) by 2 and subtracting (iii) from (i),
Or, -2x2 – 5x3 = 13 …(v)
Adding equation (iv) and (v),
0 = 20.
Now, we have the following three equations.
Or, x1 + x2 + x3 = -3….(i)
Or, 2x2 + 5x3 = 7 ….(iv)
Or, 0.x3 = 20 ….(vi)
Hence, no value of x3 satisfies the equation (vi),
So, the system has no solution.