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The equation |1-x| + x^(2) = 5 has :...

The equation `|1-x| + x^(2) = 5` has :

A

A rational root and an irrational root

B

Two rational roots

C

Two irrational roots

D

No real roots

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The correct Answer is:
To solve the equation \( |1 - x| + x^2 = 5 \), we need to consider two cases due to the absolute value. ### Step 1: Set up the cases based on the absolute value The expression \( |1 - x| \) can be split into two cases: 1. **Case 1**: \( 1 - x \geq 0 \) (which implies \( x \leq 1 \)) - In this case, \( |1 - x| = 1 - x \). - The equation becomes: \[ 1 - x + x^2 = 5 \] 2. **Case 2**: \( 1 - x < 0 \) (which implies \( x > 1 \)) - In this case, \( |1 - x| = -(1 - x) = x - 1 \). - The equation becomes: \[ x - 1 + x^2 = 5 \] ### Step 2: Solve Case 1 For **Case 1**: \[ 1 - x + x^2 = 5 \] Rearranging gives: \[ x^2 - x + 1 - 5 = 0 \implies x^2 - x - 4 = 0 \] Now, we can use the quadratic formula: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] where \( a = 1, b = -1, c = -4 \): \[ x = \frac{-(-1) \pm \sqrt{(-1)^2 - 4 \cdot 1 \cdot (-4)}}{2 \cdot 1} \] \[ x = \frac{1 \pm \sqrt{1 + 16}}{2} = \frac{1 \pm \sqrt{17}}{2} \] ### Step 3: Solve Case 2 For **Case 2**: \[ x - 1 + x^2 = 5 \] Rearranging gives: \[ x^2 + x - 1 - 5 = 0 \implies x^2 + x - 6 = 0 \] Now, we can use the quadratic formula: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \] where \( a = 1, b = 1, c = -6 \): \[ x = \frac{-1 \pm \sqrt{1^2 - 4 \cdot 1 \cdot (-6)}}{2 \cdot 1} \] \[ x = \frac{-1 \pm \sqrt{1 + 24}}{2} = \frac{-1 \pm \sqrt{25}}{2} \] \[ x = \frac{-1 \pm 5}{2} \] Calculating the two roots: 1. \( x = \frac{4}{2} = 2 \) 2. \( x = \frac{-6}{2} = -3 \) ### Step 4: Collect the roots From **Case 1**, the roots are: \[ x = \frac{1 + \sqrt{17}}{2} \quad \text{and} \quad x = \frac{1 - \sqrt{17}}{2} \] From **Case 2**, the roots are: \[ x = 2 \quad \text{and} \quad x = -3 \] ### Step 5: Determine the nature of the roots - The roots from Case 1 (\( \frac{1 + \sqrt{17}}{2} \) and \( \frac{1 - \sqrt{17}}{2} \)) are one rational and one irrational root. - The roots from Case 2 (2 and -3) are both rational. ### Conclusion Thus, the equation \( |1 - x| + x^2 = 5 \) has a total of **two rational roots and two irrational roots**. ### Final Answer: The correct option is **(b) two rational roots**. ---
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