Math Problem Statement

Solve the equation 4/(x + 1) - 4/(x^2 - 2x - 3) = 1/(3 - x).

Solution

Let's analyze and solve the given equation:

4x+14x22x3=13x\frac{4}{x+1} - \frac{4}{x^2 - 2x - 3} = \frac{1}{3 - x}

Step 1: Factorize the quadratic term

The quadratic term in the second denominator x22x3x^2 - 2x - 3 can be factorized as:

x22x3=(x3)(x+1)x^2 - 2x - 3 = (x - 3)(x + 1)

Thus, the equation becomes:

4x+14(x3)(x+1)=13x\frac{4}{x+1} - \frac{4}{(x-3)(x+1)} = \frac{1}{3 - x}

Step 2: Express 3x3 - x as (x3)-(x - 3)

Notice that 3x3 - x can be rewritten as (x3)-(x - 3). So, the right-hand side becomes:

13x=1x3\frac{1}{3 - x} = -\frac{1}{x - 3}

Now, the equation looks like:

4x+14(x3)(x+1)=1x3\frac{4}{x+1} - \frac{4}{(x-3)(x+1)} = -\frac{1}{x-3}

Step 3: Combine the terms on the left-hand side

We need a common denominator on the left-hand side. The common denominator is (x3)(x+1)(x - 3)(x + 1), so:

4x+1=4(x3)(x3)(x+1)\frac{4}{x+1} = \frac{4(x - 3)}{(x - 3)(x + 1)}

Thus, the left-hand side becomes:

4(x3)(x3)(x+1)4(x3)(x+1)=4(x3)4(x3)(x+1)\frac{4(x - 3)}{(x - 3)(x + 1)} - \frac{4}{(x - 3)(x+1)} = \frac{4(x - 3) - 4}{(x - 3)(x + 1)}

Simplifying the numerator:

4(x3)4=4x124=4x164(x - 3) - 4 = 4x - 12 - 4 = 4x - 16

So, the left-hand side is now:

4x16(x3)(x+1)\frac{4x - 16}{(x - 3)(x + 1)}

Step 4: Set up the equation

Now the equation becomes:

4x16(x3)(x+1)=1x3\frac{4x - 16}{(x - 3)(x + 1)} = -\frac{1}{x - 3}

Step 5: Multiply both sides by (x3)(x - 3)

To eliminate the denominator x3x - 3, we multiply both sides by (x3)(x - 3) (but be careful with the restriction x3x \neq 3):

4x16x+1=1\frac{4x - 16}{x + 1} = -1

Step 6: Solve for xx

Multiply both sides by x+1x + 1:

4x16=(x+1)4x - 16 = -(x + 1)

Expand the right-hand side:

4x16=x14x - 16 = -x - 1

Now, collect like terms:

4x+x=1+164x + x = -1 + 16

5x=155x = 15

Finally, solve for xx:

x=3x = 3

Step 7: Verify the solution

However, x=3x = 3 is not a valid solution because it would make the denominators (x3)(x - 3) zero. Therefore, the solution x=3x = 3 must be rejected.

Final Conclusion:

There is no valid solution for this equation, since x=3x = 3 is not allowed.

Would you like more details on any step or have further questions? Here are 5 related questions for practice:

  1. How do you factor quadratic expressions like x22x3x^2 - 2x - 3?
  2. What happens if a solution makes a denominator zero in a rational equation?
  3. How can you rewrite fractions with common denominators?
  4. Why do we reject certain solutions in rational equations?
  5. How do we handle negative signs when manipulating rational equations?

Tip: Always check your solutions in the original equation to ensure they don't violate any restrictions (like making a denominator zero).

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Equations
Factoring

Formulas

Factoring quadratic expressions: ax^2 + bx + c
Common denominator for fractions
Solving linear equations

Theorems

Factorization Theorem
Zero Denominator Rule

Suitable Grade Level

Grades 10-12