+1 vote
in JEE by kratos

Show that the equations 2x + 6y + 11 = 0, 6x + 20y - 6z + 3 = 0 and 6y - 18z + 1 = 0 are not consistent.

1 Answer

+6 votes
by kratos
 
Best answer

So, the system is inconsistent.

Alternate method: The given system of equations is equivalent to the single matrix equation:

We shall reduce the coefficient matrix A to triangular form by E-row operations on it and apply the same operations on the right-hand side, i.e. on the matrix B.

Performing R2 → R2 - 3R1, we have

Performing R3 → R3 - 3R2, we have

The last equation of this system is 0x + 0y + 0z = -91. This shows that the given system is not consistent.

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