Question

Difficulty: HardRational and Radical Expressions and Equations

If xx is a real number, what is the sum of all distinct real solutions to the rational equation 3(x2)22x2=1\frac{3}{(x-2)^2} - \frac{2}{x-2} = 1?

  1. A
    3
  2. B
    -3
  3. C
    -2
  4. 2Answer
  5. E
    4

Answer

The sum of all distinct real solutions is 2.
The correct answer is obtained by multiplying the equation by the least common denominator, (x2)2(x-2)^2, which yields the quadratic equation x22x3=0x^2 - 2x - 3 = 0. Factoring this equation gives two solutions: 33 and 1-1. Since neither value makes the original denominator equal to zero, both are valid solutions. Summing these values gives a result of 22.

Step-by-Step Solution

1
Identify the domain constraints of the rational equation.
The denominator x2x-2 cannot be zero, so the domain constraint is x2x \neq 2.
Division by zero is undefined.
2
Eliminate the denominators by multiplying the entire equation by the least common denominator, which is (x2)2(x-2)^2.
32(x2)=(x2)23 - 2(x-2) = (x-2)^2
This transforms the rational equation into a polynomial equation.
3
Expand both sides of the equation and combine like terms.
32x+4=x24x+4    72x=x24x+43 - 2x + 4 = x^2 - 4x + 4 \implies 7 - 2x = x^2 - 4x + 4
Standard algebraic expansion simplifies the equation into a quadratic form.
4
Rearrange the quadratic equation into standard form ax2+bx+c=0ax^2 + bx + c = 0.
x22x3=0x^2 - 2x - 3 = 0
Setting the equation to zero allows us to solve for xx by factoring.
5
Factor the quadratic equation.
(x3)(x+1)=0    x=3(x-3)(x+1) = 0 \implies x = 3 or x=1x = -1
Factoring finds the values of xx that satisfy the quadratic equation.
6
Verify if the potential solutions satisfy the domain constraint and calculate their sum.
Both 33 and 1-1 are within the domain (x2x \neq 2). The sum is 3+(1)=23 + (-1) = 2.
Extraneous solutions must be discarded before calculating the final sum.

Key Concept

Solving rational equations by clearing denominators and verifying domain constraints
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