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The number of values of lamda for which ...

The number of values of `lamda` for which `(lamda^(2)-3 lamda +2) x^(2) +(lamda^(2)-5 lamda +6) x +lamda^(2)-4=0` is an identity in x is

A

1

B

2

C

-2

D

0

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The correct Answer is:
To solve the problem, we need to determine the number of values of \( \lambda \) for which the quadratic equation \[ (\lambda^2 - 3\lambda + 2)x^2 + (\lambda^2 - 5\lambda + 6)x + (\lambda^2 - 4) = 0 \] is an identity in \( x \). This means that the coefficients of \( x^2 \), \( x \), and the constant term must all be zero. ### Step 1: Set the coefficient of \( x^2 \) to zero The coefficient of \( x^2 \) is \( \lambda^2 - 3\lambda + 2 \). We set it to zero: \[ \lambda^2 - 3\lambda + 2 = 0 \] ### Step 2: Factor the quadratic equation Factoring the quadratic gives: \[ (\lambda - 2)(\lambda - 1) = 0 \] ### Step 3: Find the values of \( \lambda \) From the factors, we find: \[ \lambda - 2 = 0 \quad \Rightarrow \quad \lambda = 2 \] \[ \lambda - 1 = 0 \quad \Rightarrow \quad \lambda = 1 \] So, the values of \( \lambda \) from this equation are \( \lambda = 1 \) and \( \lambda = 2 \). ### Step 4: Set the coefficient of \( x \) to zero Next, we set the coefficient of \( x \) to zero: \[ \lambda^2 - 5\lambda + 6 = 0 \] ### Step 5: Factor this quadratic equation Factoring gives: \[ (\lambda - 3)(\lambda - 2) = 0 \] ### Step 6: Find the values of \( \lambda \) From this factorization, we find: \[ \lambda - 3 = 0 \quad \Rightarrow \quad \lambda = 3 \] \[ \lambda - 2 = 0 \quad \Rightarrow \quad \lambda = 2 \] So, the values of \( \lambda \) from this equation are \( \lambda = 2 \) and \( \lambda = 3 \). ### Step 7: Set the constant term to zero Now, we set the constant term to zero: \[ \lambda^2 - 4 = 0 \] ### Step 8: Solve for \( \lambda \) This can be factored as: \[ (\lambda - 2)(\lambda + 2) = 0 \] ### Step 9: Find the values of \( \lambda \) From this factorization, we find: \[ \lambda - 2 = 0 \quad \Rightarrow \quad \lambda = 2 \] \[ \lambda + 2 = 0 \quad \Rightarrow \quad \lambda = -2 \] So, the values of \( \lambda \) from this equation are \( \lambda = 2 \) and \( \lambda = -2 \). ### Step 10: Identify common values of \( \lambda \) Now we have the values of \( \lambda \) from all three conditions: 1. From \( a = 0 \): \( \lambda = 1, 2 \) 2. From \( b = 0 \): \( \lambda = 2, 3 \) 3. From \( c = 0 \): \( \lambda = 2, -2 \) The common value across all three conditions is \( \lambda = 2 \). ### Conclusion Thus, there is only **one value of \( \lambda \)** for which the given quadratic equation is an identity in \( x \). The answer is: \[ \text{Number of values of } \lambda = 1 \] ---
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ML KHANNA-THEORY OF QUADRATIC EQUATIONS -Self Assessment Test
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  3. The number of real solutions of the equation |x|^(2)-3|x|+2=0 is :

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  4. Find the number of solution of the equation e^(sinx)-e^(-sinx)-4=0

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  5. The roots of the equation (p-q) x^(2)+(q-r) x+(r-p)=0 are

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  6. If one root of x^(2) + px+12 = 0 is 4, while the equation x ^(2)...

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  7. Let alpha and beta are the roots of the equation x^(2) + x + 1 = 0 The...

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  8. If the quadratic equation x^(2) +ax +b =0 and x^(2) +bx +a =0 (a ne b...

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  9. If the roots of the equation x^2-8x+a^2-6a=0 are real distinct, then f...

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  10. The value of k for which the equation x^(2)-(3k-1)x+2k^(2)+2k=11 have ...

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  11. if 2 = I sqrt3 be a root of the equation x^(2) + px + q =0, where p ...

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  12. The number of solutions of the pair of equations 2s in^2theta-cos2thet...

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  13. If alpha, beta are roots of the equations Ax^(2)+Bx+C=0. Then value of...

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  14. If the equation x^(2)+px+q=0 and x^(2)+qx+p=0 have a common root then ...

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  15. If alpha and beta (alpha lt beta) are the roots of the equation x^(2) ...

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  16. If 2a+3b+6c=0, then prove that at least one root of the equation a x^2...

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  17. If the roots of the equation (x^2-b x)/(a x-c)=(m-1)/(m+1) are equal t...

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  18. If sin alpha, cos alpha are the roots of the equation ax^(2)+bx+c=0, t...

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  19. If alpha, beta are the roots of x^(2)-ax+b =0 and If alpha^(n)+beta^(n...

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  20. The value of a for which one root of the quadratic equation (a^2-5a+3)...

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  21. If a,b, c are in G.P., then the equations ax^(2) + 2bx + c = 0 and dx^...

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