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Question

What is the nature of the roots of the following quadratic equation?

$\text{x} - \frac{1}{\text{x}} = 17$

The correct answer is
Real and distinct (irrational)

Determine Nature of Roots for Quadratic Equation

First, convert the given equation into the standard quadratic form, $ax^2 + bx + c = 0$.

Given equation: $\text{x} - \frac{1}{\text{x}} = 17$.

  • Multiply by $x$ (assuming $x \neq 0$): $x(x) - x(\frac{1}{x}) = 17x$ $x^2 - 1 = 17x$
  • Rearrange into standard form: $x^2 - 17x - 1 = 0$

Identify the coefficients $a$, $b$, and $c$ from $x^2 - 17x - 1 = 0$:

  • $a = 1$
  • $b = -17$
  • $c = -1$

Calculate Discriminant to Find Root Nature

The nature of the roots depends on the discriminant, calculated using the formula $\Delta = b^2 - 4ac$.

  • Calculate $\Delta$: $\Delta = (-17)^2 - 4(1)(-1)$ $\Delta = 289 - (-4)$ $\Delta = 289 + 4$ $\Delta = 293$

Analyze Discriminant Result

Analyze the value of the discriminant, $\Delta = 293$.

  • Since $\Delta = 293 > 0$, the roots are real and distinct.
  • To determine if they are rational or irrational, check if $\Delta$ is a perfect square. $17^2 = 289$ and $18^2 = 324$. Since 293 is between these squares, it is not a perfect square.
  • Therefore, the distinct real roots are irrational.

Conclusion: The roots of the equation $\text{x} - \frac{1}{\text{x}} = 17$ are real and distinct (irrational).

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Important Questions from Quadratic equation

  1. What number should be subtracted from x3−4x2−8x+11 to make the number divisible by (x+2)?

  2. Find the value of K if the quadratic equations $2x^2 + Kx + 8 = 0$ and $3x^2 + 4x + 12 = 0$ have both roots common.
  3. If sum and product of the roots of a quadratic equation are $(4-3\sqrt{2})$ and -28, respectively, then find the quadratic equation.
  4. If the quadratic equations $4x^2 + bx + 3 = 0$ and $8x^2 + 4x + c = 0$ have both the roots common, find the values for b and c, respectively.
  5. Determine the nature of the roots of the quadratic equation $3x^2 + 2x + 5 = 0$.
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