Home
Class 12
MATHS
If a ne 0 and the equation ax ^(2)+bx+c=...

If `a ne 0` and the equation `ax ^(2)+bx+c=0` has two roots `alpha and beta` such thet `alpha lt -3 and beta gt 2.` Which of the following is always true ?

A

`a (a+|b| +c) gt 0`

B

`a (a+|b| +c) lt 0`

C

`9a -3b + c gt 0`

D

`(9a -3b+c) (4a +2b +c) lt 0`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the given quadratic equation \( ax^2 + bx + c = 0 \) with roots \( \alpha \) and \( \beta \) such that \( \alpha < -3 \) and \( \beta > 2 \). We will explore the implications of these conditions on the coefficients \( a \), \( b \), and \( c \). ### Step 1: Understanding the Roots The roots of the quadratic equation \( ax^2 + bx + c = 0 \) can be expressed using Vieta's formulas: - The sum of the roots \( \alpha + \beta = -\frac{b}{a} \) - The product of the roots \( \alpha \beta = \frac{c}{a} \) ### Step 2: Analyzing the Conditions on Roots Given the conditions \( \alpha < -3 \) and \( \beta > 2 \): - Since \( \alpha < -3 \), we can say \( \alpha + \beta < -3 + 2 = -1 \). - This implies that \( -\frac{b}{a} < -1 \), which leads to \( \frac{b}{a} > 1 \) or \( b > a \) (if \( a > 0 \)) or \( b < a \) (if \( a < 0 \)). ### Step 3: Analyzing the Product of the Roots From the product of the roots: - Since \( \alpha < -3 \) and \( \beta > 2 \), we have \( \alpha \beta < -3 \cdot 2 = -6 \). - This implies \( \frac{c}{a} < -6 \), leading to \( c < -6a \) (if \( a > 0 \)) or \( c > -6a \) (if \( a < 0 \)). ### Step 4: Considering the Sign of \( a \) We need to consider two cases based on the sign of \( a \): **Case 1: \( a > 0 \)** - The parabola opens upwards. - The conditions imply \( b > a \) and \( c < -6a \). **Case 2: \( a < 0 \)** - The parabola opens downwards. - The conditions imply \( b < a \) and \( c > -6a \). ### Step 5: Conclusion Based on the analysis, we can conclude that the following statements are always true: - If \( a > 0 \), then \( b > a \) and \( c < -6a \). - If \( a < 0 \), then \( b < a \) and \( c > -6a \). Thus, the correct answer among the options provided would be the one that captures the relationship between \( a \), \( b \), and \( c \) based on the conditions of the roots.
Promotional Banner

Topper's Solved these Questions

  • QUADRATIC EQUATIONS

    VIKAS GUPTA (BLACK BOOK) ENGLISH|Exercise EXERCISE (ONE OR MORE THAN ONE ANSWER IS/ARE CORRECT)|42 Videos
  • QUADRATIC EQUATIONS

    VIKAS GUPTA (BLACK BOOK) ENGLISH|Exercise EXERCISE (COMPREHENSION TYPE PROBLEMS)|23 Videos
  • PROBABILITY

    VIKAS GUPTA (BLACK BOOK) ENGLISH|Exercise Exercise -5 : Subjective Type problems|11 Videos
  • SEQUENCE AND SERIES

    VIKAS GUPTA (BLACK BOOK) ENGLISH|Exercise EXERCISE (SUBJECTIVE TYPE PROBLEMS)|21 Videos

Similar Questions

Explore conceptually related problems

Statement-1: If a ne 0 and the equation ax^(2) + bx + c = 0 has two roots alpha and beta such that alpha lt -1 and beta gt 1 , then a+|b|+c and a have the opposite sign. Statement-2: If ax^(2) + bx + c , is same as that of 'a' for all real values of x except for those values of x lying between the roots.

ax^2 + bx + c = 0(a > 0), has two roots alpha and beta such alpha 2, then

ax^2 + bx + c = 0(a > 0), has two roots alpha and beta such alpha 2, then

ax^2 + bx + c = 0(a > 0), has two roots alpha and beta such alpha 2, then

Let a,b,c in R and a gt 0 . If the quadratic equation ax^(2) +bx +c=0 has two real roots alpha and beta such that alpha gt -1 and beta gt 1 , then show that 1 + |b/a| + c/a gt 0

If a, b, c are real if ax^(2)+ bx + c = 0 has two real roots alpha, beta where a lt -1, beta gt 1 then

The quadratic equation x^(2)-9x+3=0 has roots alpha and beta.If x^(2)-bx-c=0 has roots alpha^(2)and beta^(2), then (b,c) is

If alpha, beta are roots of the equation ax^2 + bx + c = 0 then the equation whose roots are 2alpha + 3beta and 3alpha + 2beta is

If alpha, beta are the roots of the equation x^(2)+alphax + beta = 0 such that alpha ne beta and ||x-beta|-alpha|| lt alpha , then

lf alpha and beta are the roots of the equation x^2-ax + b = 0 and A_n = alpha^n + beta^n , then which of the following is true ?

VIKAS GUPTA (BLACK BOOK) ENGLISH-QUADRATIC EQUATIONS -EXERCISE (SUBJECTIVE TYPE PROBLEMS)
  1. If a ne 0 and the equation ax ^(2)+bx+c=0 has two roots alpha and beta...

    Text Solution

    |

  2. Let f (x) =ax ^(2) + bx+ c where a,b,c are integers. If sin ""pi/7. si...

    Text Solution

    |

  3. Let a, b, c, d be distinct integers such that the equation (x - a) (x ...

    Text Solution

    |

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

    Text Solution

    |

  5. The number of positive integral values of , m le 16 for which the equa...

    Text Solution

    |

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

    Text Solution

    |

  7. The least positive integral value of 'x' satisfying (e^x-2)(sin(x+pi/...

    Text Solution

    |

  8. The integral values of x for which x ^(2) + 17 x +7 is perfect square ...

    Text Solution

    |

  9. Let p(x) =x^6-x^5-x^3-x^2-x and alpha, beta, gamma, delta are the root...

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

  13. If the expression a x^4+b x^3-x^2+2x+3 has remainder 4x+3 when divided...

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

  16. The expression x^2 + 2xy + ky^2 + 2x + k = 0 can be resolved into two ...

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |

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

    Text Solution

    |