Question

Difficulty: MediumEquivalent Algebraic Expressions

For all x>1x > 1, which of the following is equivalent to the expression 4x212x16x2+x23x+2\frac{4x^2 - 1}{2x - 1} - \frac{6x^2 + x - 2}{3x + 2}?

  1. A
    0
  2. 2Answer
  3. C
    -2
  4. D
    4x

Answer

2
Factoring the numerators allows the expression to be simplified. The first term becomes 2x+12x + 1, and the second term becomes 2x12x - 1. Subtracting the second term from the first and distributing the negative sign results in (2x+1)(2x1)=2x+12x+1=2(2x + 1) - (2x - 1) = 2x + 1 - 2x + 1 = 2.

Step-by-Step Solution

1
Factor the numerator of the first rational term, 4x214x^2 - 1, using the difference of squares identity.
4x21=(2x1)(2x+1)4x^2 - 1 = (2x - 1)(2x + 1)
To identify and divide out common factors between the numerator and denominator.
2
Simplify the first term by dividing the factored numerator by its denominator, 2x12x - 1.
(2x1)(2x+1)2x1=2x+1\frac{(2x - 1)(2x + 1)}{2x - 1} = 2x + 1
Since x>1x > 1, 2x102x - 1 \neq 0, allowing the division.
3
Factor the numerator of the second rational term, 6x2+x26x^2 + x - 2.
6x2+x2=(2x1)(3x+2)6x^2 + x - 2 = (2x - 1)(3x + 2)
To find common factors that can be simplified with the denominator.
4
Simplify the second term by dividing the factored numerator by its denominator, 3x+23x + 2.
(2x1)(3x+2)3x+2=2x1\frac{(2x - 1)(3x + 2)}{3x + 2} = 2x - 1
Since x>1x > 1, 3x+203x + 2 \neq 0, allowing the division.
5
Subtract the second simplified expression from the first, ensuring that the negative sign is correctly distributed to all terms.
(2x+1)(2x1)=2x+12x+1=2(2x + 1) - (2x - 1) = 2x + 1 - 2x + 1 = 2
To combine the terms and find the final equivalent value of the entire expression.

Key Concept

Equivalent Algebraic Expressions
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