4 Maths -- System of Linear Equations

Examine consistency. Solve if possible.x1 + x2 + x3 = -3,3x1 + x2 – 2x3 = -2,2x1 + 4x2 + 7x3 = 7

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.

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