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Zorluk: OrtaEquivalent Algebraic Expressions

For all x>2x > 2, which of the following is equivalent to the expression 3x25x2x24x1x+2\frac{3x^2 - 5x - 2}{x^2 - 4} - \frac{x - 1}{x + 2}?

  1. A
    2xx+2\frac{2x}{x + 2}
  2. 2x+2x+2\frac{2x + 2}{x + 2}Cevap
  3. C
    2x+2x2\frac{2x + 2}{x - 2}
  4. D
    x+1x+2\frac{x + 1}{x + 2}

Cevap

The expression is equivalent to 2x+2x+2\frac{2x + 2}{x + 2}.
The correct answer is obtained by first factoring the first term: 3x25x2x24=(3x+1)(x2)(x2)(x+2)\frac{3x^2 - 5x - 2}{x^2 - 4} = \frac{(3x + 1)(x - 2)}{(x - 2)(x + 2)}. Canceling the common factor of x2x - 2 yields 3x+1x+2\frac{3x + 1}{x + 2}. Subtracting the second term gives 3x+1(x1)x+2=3x+1x+1x+2=2x+2x+2\frac{3x + 1 - (x - 1)}{x + 2} = \frac{3x + 1 - x + 1}{x + 2} = \frac{2x + 2}{x + 2}.

Adım Adım Çözüm

1
Factor the numerator and the denominator of the first term of the expression.
The numerator factors as 3x25x2=(3x+1)(x2)3x^2 - 5x - 2 = (3x + 1)(x - 2), and the denominator factors as x24=(x2)(x+2)x^2 - 4 = (x - 2)(x + 2).
This allows common factors in the numerator and denominator to be identified and canceled.
2
Simplify the first term by canceling the common factor (x2)(x - 2) for x>2x > 2.
The first term simplifies to 3x+1x+2\frac{3x + 1}{x + 2}.
For x>2x > 2, x20x - 2 \neq 0, so we can divide both numerator and denominator by x2x - 2 to simplify the fraction.
3
Subtract the second term from the simplified first term.
The expression becomes 3x+1x+2x1x+2=(3x+1)(x1)x+2\frac{3x + 1}{x + 2} - \frac{x - 1}{x + 2} = \frac{(3x + 1) - (x - 1)}{x + 2}.
Since both fractions have the same denominator, x+2x + 2, their numerators can be subtracted directly.
4
Distribute the negative sign in the numerator and combine like terms.
3x+1x+1x+2=2x+2x+2\frac{3x + 1 - x + 1}{x + 2} = \frac{2x + 2}{x + 2}.
Distributing the subtraction to both terms in the parenthesis (x1)(x - 1) gives x+1-x + 1. Combining 3xx3x - x yields 2x2x, and 1+11 + 1 yields 22.

Anahtar Kavram

Simplifying rational expressions by factoring and performing algebraic operations with common denominators.
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