SOLVE THE EQUATION ELIMINATING ANY EXTRANEOUS SOLUTIONS

When we multiply or divide an equation by an expression containing variables, the resulting equation may have solutions that are not solutions of the original equation. These are extraneous solutions.

For this reason we must check each solution of the resulting equation in the original equation.

Example 1 :

Solve for x :

2x/(x - 1) + 1/(x - 3)  =   2/x2 - 4x + 3

Solution :

2x/(x - 1) + 1/(x - 3)  =   2/x2 - 4x + 3

Factoring the quadratic equation x2 - 4x + 3, we get factors as (x - 1) (x - 3).

2x/(x - 1) + 1/(x - 3)  =   2/(x - 1) (x - 3)  --(1)

2x(x - 3) + 1(x - 1)  =  2

2x2 - 6x + x - 1  =  2

2x2 - 5x - 1 - 2  =  0

2x2 - 5x - 3  =  0

(2x + 1) (x - 3)  =  0

2x + 1  =  0

x  =  -1/2

x - 3  =  0

 x  =  3

To check whether above values are solution or not, we apply the values in (1).

If x  =  -1/2, we get the defined value.

If x  =  3, we get undefined value. So, only x  =  -1/2 is a solution.

Example 2 :

Solve for x :

(x - 3)/x  +  3/(x + 2)  +  6/(x2 + 2x)  =  0

Solution :

(x - 3)/x  +  3/(x + 2)  +  6/(x2 + 2x)  =  0

(x - 3)/x  +  3/(x + 2)  +  6/x(x + 2)  =  0

Least common multiple is x (x + 2).

(x - 3)(x + 2) + 3x  +  6  =  0

x2 - x - 6 + 3x + 6  =  0

x2 + 2x  =  0

x(x + 2)  =  0

x  =  0  and x + 2  =  0

x  =  0 and x  =  -2

Substituting x  =  0 or x  =  -2 into the original equation results in the division is zero. So both of these numbers are extraneous solution. So the original equation has no solution.

Kindly mail your feedback to v4formath@gmail.com

We always appreciate your feedback.

©All rights reserved. onlinemath4all.com

Recent Articles

  1. Trigonometry Even and Odd Iidentities

    May 05, 24 12:25 AM

    ASTCnew.png
    Trigonometry Even and Odd Iidentities

    Read More

  2. SOHCAHTOA Worksheet

    May 03, 24 08:50 PM

    sohcahtoa39
    SOHCAHTOA Worksheet

    Read More

  3. Trigonometry Pythagorean Identities

    May 02, 24 11:43 PM

    Trigonometry Pythagorean Identities

    Read More