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If a, b, c are real then (b-x)^(2)-4(a-x...

If a, b, c are real then `(b-x)^(2)-4(a-x) (c-x)=0` will have always roots which are

A

real and equal

B

real and distinct

C

imaginary

D

both 1 and 2

Text Solution

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The correct Answer is:
To determine the nature of the roots of the equation \((b-x)^{2} - 4(a-x)(c-x) = 0\), we will follow these steps: ### Step 1: Expand the Equation Start by expanding the left-hand side of the equation. \[ (b - x)^{2} - 4(a - x)(c - x) = 0 \] Expanding \((b - x)^{2}\): \[ (b - x)^{2} = b^{2} - 2bx + x^{2} \] Expanding \(4(a - x)(c - x)\): \[ 4(a - x)(c - x) = 4(ac - ax - cx + x^{2}) = 4ac - 4ax - 4cx + 4x^{2} \] Putting it all together: \[ b^{2} - 2bx + x^{2} - (4ac - 4ax - 4cx + 4x^{2}) = 0 \] ### Step 2: Combine Like Terms Now, combine the terms: \[ b^{2} - 2bx + x^{2} - 4ac + 4ax + 4cx - 4x^{2} = 0 \] This simplifies to: \[ b^{2} - 4ac + (4a - 2b + 4c)x - 3x^{2} = 0 \] ### Step 3: Rearrange into Standard Quadratic Form Rearranging gives us: \[ -3x^{2} + (4a - 2b + 4c)x + (b^{2} - 4ac) = 0 \] This is a quadratic equation of the form \(Ax^{2} + Bx + C = 0\), where: - \(A = -3\) - \(B = 4a - 2b + 4c\) - \(C = b^{2} - 4ac\) ### Step 4: Find the Discriminant To determine the nature of the roots, we calculate the discriminant \(D\): \[ D = B^{2} - 4AC \] Substituting the values: \[ D = (4a - 2b + 4c)^{2} - 4(-3)(b^{2} - 4ac) \] ### Step 5: Simplify the Discriminant Calculating \(D\): \[ D = (4a - 2b + 4c)^{2} + 12(b^{2} - 4ac) \] ### Step 6: Analyze the Discriminant The expression \((4a - 2b + 4c)^{2}\) is always non-negative since it is a square. The term \(12(b^{2} - 4ac)\) can be positive, negative, or zero depending on the values of \(a\), \(b\), and \(c\). However, the term \(b^{2} - 4ac\) is a standard form that can be analyzed further. ### Conclusion Since \((4a - 2b + 4c)^{2}\) is always non-negative and \(12(b^{2} - 4ac)\) can also yield a positive discriminant, we conclude that the discriminant \(D\) is always greater than or equal to zero. Thus, the roots of the equation are **real and distinct** when \(D > 0\) and **real and equal** when \(D = 0\). ### Final Answer The roots of the equation will always be **real and distinct**. ---
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