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The number of positive integral values of `m`, `m le 16` for which the equation `(x^(2) +x+1) ^(2) - (m-3)(x^(2) +x+1) +m=0,` has 4 distinct real root is:

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To solve the problem, we need to find the number of positive integral values of \( m \) (where \( m \leq 16 \)) for which the equation \[ (x^2 + x + 1)^2 - (m-3)(x^2 + x + 1) + m = 0 \] has 4 distinct real roots. ### Step 1: Substitute \( t = x^2 + x + 1 \) Let \( t = x^2 + x + 1 \). Then the equation becomes: \[ t^2 - (m-3)t + m = 0 \] ### Step 2: Analyze the quadratic in \( t \) For the quadratic equation \( t^2 - (m-3)t + m = 0 \) to have real roots, the discriminant must be greater than or equal to zero: \[ D = (m-3)^2 - 4 \cdot 1 \cdot m \geq 0 \] ### Step 3: Calculate the discriminant Calculating the discriminant: \[ D = (m-3)^2 - 4m = m^2 - 6m + 9 - 4m = m^2 - 10m + 9 \] Setting the discriminant greater than or equal to zero: \[ m^2 - 10m + 9 \geq 0 \] ### Step 4: Solve the quadratic inequality To find the roots of the quadratic equation \( m^2 - 10m + 9 = 0 \): Using the quadratic formula: \[ m = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} = \frac{10 \pm \sqrt{(-10)^2 - 4 \cdot 1 \cdot 9}}{2 \cdot 1} = \frac{10 \pm \sqrt{100 - 36}}{2} = \frac{10 \pm \sqrt{64}}{2} = \frac{10 \pm 8}{2} \] Thus, the roots are: \[ m = \frac{18}{2} = 9 \quad \text{and} \quad m = \frac{2}{2} = 1 \] ### Step 5: Analyze the intervals The quadratic \( m^2 - 10m + 9 \) opens upwards (since the coefficient of \( m^2 \) is positive). Therefore, the inequality \( m^2 - 10m + 9 \geq 0 \) holds true for: \[ m \leq 1 \quad \text{or} \quad m \geq 9 \] ### Step 6: Find the range of \( m \) Since we are interested in positive integral values of \( m \) such that \( m \leq 16 \), we consider: 1. \( m = 1 \) (from \( m \leq 1 \)) 2. \( m = 9, 10, 11, 12, 13, 14, 15, 16 \) (from \( m \geq 9 \)) ### Step 7: Count the valid values of \( m \) The valid positive integral values of \( m \) are: - From \( m \leq 1 \): \( 1 \) - From \( m \geq 9 \): \( 9, 10, 11, 12, 13, 14, 15, 16 \) Thus, the total number of valid values of \( m \) is: \[ 1 + 8 = 9 \] ### Conclusion The number of positive integral values of \( m \) such that the equation has 4 distinct real roots is **9**.
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VK JAISWAL ENGLISH-QUADRATIC EQUATIONS -EXERCISE (SUBJECTIVE TYPE PROBLEMS)
  1. Let a,b,c,d be distinct integers such that the equation (x-a) (x-b) (x...

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  2. Consider the equation (x^2 + x + 1)^2-(m-3)(x^2 + x + 1) +m=0--(1), w...

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  3. The number of positive integral values of m, m le 16 for which the equ...

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  4. If the equation (m^(2) -12 )x^(4) -8x ^(2)-4=0 has no real roots, then...

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  5. The least rositive integral value of 'x' satisfying (e ^(x) -2) (sin (...

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  7. Let P (x)=x ^(6) -x ^(5) -x ^(3) -x ^(2) -x and alpha, beta, gamma, de...

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  8. The number of real values of 'a' for which the largest value of the fu...

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  9. The number of all values of n, (whre pi is a whole number ) for which ...

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  10. The number of negative intergral values of m for which the expression ...

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  11. If the expression ax ^(4)+bx^(3)-x ^(2)+2x+3 has the remainder 4x +3 w...

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  12. The smallest value of k for which both roots of the equation x^(2)-8kx...

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  13. If x ^(2) -3x+2 is a factor of x ^(4) -px ^(2) +q=0, then p+q=

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  14. The sum of all real values of k for which the expression x ^(2)+2xy +k...

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  15. The curve y=(lambda=1)x^2+2 intersects the curve y=lambdax+3 in exactl...

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  16. Find the number of integral vaues of 'a' for which the range of functi...

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  17. When x ^(100) is divided by x ^(2) -3x +2, the remainder is (2 ^(k +1)...

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  18. Let p(x)=0 be a polynomial equation of the least possible degree, with...

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  19. The range of value's of k for which the equation 2 cos^(4) x - sin^(4...

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  20. Let p (x) be a polynomial with real coefficient and p (x)-p'(x) =x^(2)...

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