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Question

Find the discriminant of the equation $\frac{x-3}{x-4} + \frac{x-6}{x-5} = \frac{5}{2}$

The correct answer is
-7

Simplify Rational Equation

Begin with the given rational equation:

$ \frac{x-3}{x-4} + \frac{x-6}{x-5} = \frac{5}{2} $

Combine fractions on the left side using a common denominator:

$ \frac{(x-3)(x-5) + (x-6)(x-4)}{(x-4)(x-5)} = \frac{5}{2} $

Expand and simplify the numerator and denominator:

  • Numerator: $ (x^2 - 8x + 15) + (x^2 - 10x + 24) = 2x^2 - 18x + 39 $
  • Denominator: $ x^2 - 9x + 20 $

Substitute back into the equation:

$ \frac{2x^2 - 18x + 39}{x^2 - 9x + 20} = \frac{5}{2} $

Cross-multiply:

$ 2(2x^2 - 18x + 39) = 5(x^2 - 9x + 20) $

$ 4x^2 - 36x + 78 = 5x^2 - 45x + 100 $

Rearrange into standard quadratic form $ ax^2 + bx + c = 0 $:

$ 0 = x^2 - 9x + 22 $

Calculate Discriminant

Identify the coefficients $a$, $b$, and $c$ from the quadratic equation $ x^2 - 9x + 22 = 0 $:

  • $ a = 1 $
  • $ b = -9 $
  • $ c = 22 $

Apply the discriminant formula $ \Delta = b^2 - 4ac $:

$ \Delta = (-9)^2 - 4(1)(22) $

$ \Delta = 81 - 88 $

$ \Delta = -7 $

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Important Questions from Quadratic Equation

  1. If 2x 2+ 5x + 1 = 0, then one of the values of \(x - \frac{1}{{2x}}\)  is:

  2. If \(a-\frac{12}{a}=1\) , where a > 0, then the value of \(a^2+\frac{16}{a^2}\) is:

  3. If x 2 – 3x + 1 = 0, then the value of  \(\frac{(x^4+\frac{1}{x^2})}{(x^2+5x+1)}\)  is:

  4. If \(\sqrt{x}{}-{1\over\sqrt{x}}=\sqrt5\) \(x \ne 0\) , then what is the value of  \((x^4+{1\over{x^2}})\over(x^2+1) \)  ?

  5. If x 2\(\frac{1}{x^2}\)  = 18, x > 0, then find the value of x \(\frac{1}{x^3}\) .

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