Example

Solving 5x2+2x33x2+x2=1x2+5x+6\frac{5}{x^2+2x-3} - \frac{3}{x^2+x-2} = \frac{1}{x^2+5x+6}

Solve the rational equation 5x2+2x33x2+x2=1x2+5x+6\frac{5}{x^2+2x-3} - \frac{3}{x^2+x-2} = \frac{1}{x^2+5x+6}.

Step 1 — Identify restricted values. Factor all three denominators: x2+2x3=(x+3)(x1)x^2+2x-3 = (x+3)(x-1) x2+x2=(x+2)(x1)x^2+x-2 = (x+2)(x-1) x2+5x+6=(x+2)(x+3)x^2+5x+6 = (x+2)(x+3) Setting each unique factor to zero gives the restricted values: x3x \neq -3, x1x \neq 1, and x2x \neq -2.

Step 2 — Find the LCD. The factored denominators share the factors (x+3)(x+3), (x1)(x-1), and (x+2)(x+2). The LCD is (x+3)(x1)(x+2)(x+3)(x-1)(x+2).

Step 3 — Clear the fractions. Multiply every term by the LCD (x+3)(x1)(x+2)(x+3)(x-1)(x+2) and cancel matching denominator factors: (x+3)(x1)(x+2)5(x+3)(x1)(x+3)(x1)(x+2)3(x+2)(x1)=(x+3)(x1)(x+2)1(x+2)(x+3)(x+3)(x-1)(x+2) \cdot \frac{5}{(x+3)(x-1)} - (x+3)(x-1)(x+2) \cdot \frac{3}{(x+2)(x-1)} = (x+3)(x-1)(x+2) \cdot \frac{1}{(x+2)(x+3)} Simplify to obtain the fraction-free equation: 5(x+2)3(x+3)=1(x1)5(x+2) - 3(x+3) = 1(x-1)

Step 4 — Solve the resulting equation. Distribute: 5x+103x9=x15x + 10 - 3x - 9 = x - 1. Combine like terms: 2x+1=x12x + 1 = x - 1. Subtract xx from both sides: x+1=1x + 1 = -1. Subtract 11 from both sides: x=2x = -2.

Step 5 — Check. The algebraic solution x=2x = -2 matches one of the restricted values. Because substituting x=2x = -2 would make two denominators equal to zero, it is an extraneous solution.

Since the algebraic process yielded only an extraneous solution, there is no solution to this equation.

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Updated 2026-04-30

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