Home
Class 11
MATHS
If b and c are odd integers, then the eq...

If `b and c` are odd integers, then the equation `x^2 + bx + c = 0` has-

A

two odd roots

B

two integer roots, one odd and one even

C

no integer roots

D

none of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to analyze the quadratic equation given by \(x^2 + bx + c = 0\), where \(b\) and \(c\) are odd integers. We will determine the nature of the roots of this equation. ### Step 1: Identify the roots using Vieta's formulas Let \(\alpha\) and \(\beta\) be the roots of the equation. According to Vieta's formulas: - The sum of the roots \(\alpha + \beta = -b\) - The product of the roots \(\alpha \beta = c\) ### Step 2: Analyze the sum of the roots Since \(b\) is an odd integer, \(-b\) is also odd. Therefore: \[ \alpha + \beta = -b \quad \text{(odd)} \] This means that the sum of the roots is odd. ### Step 3: Analyze the product of the roots Since \(c\) is an odd integer, we have: \[ \alpha \beta = c \quad \text{(odd)} \] This means that the product of the roots is odd. ### Step 4: Determine the nature of the roots 1. **Both roots odd**: If both roots \(\alpha\) and \(\beta\) were odd, then their sum \(\alpha + \beta\) would be even (since odd + odd = even). This contradicts our finding that \(\alpha + \beta\) is odd. Therefore, both roots cannot be odd. 2. **One root odd and one root even**: If one root is odd and the other is even, then their sum would still be odd (odd + even = odd). However, the product of an odd and an even number is even, which contradicts our finding that \(\alpha \beta\) is odd. Thus, this scenario is also not possible. 3. **No integer roots**: Given that both the sum and product of the roots are odd, it suggests that the roots cannot be integers. For the roots to be non-integers, the discriminant must not be a perfect square. The discriminant \(D\) is given by: \[ D = b^2 - 4ac \] Substituting \(a = 1\) and \(c\) (which is odd), we see that \(D\) is unlikely to be a perfect square, confirming that the roots are not integers. ### Conclusion Since both scenarios of having both roots odd or one root odd and one root even lead to contradictions, we conclude that the equation \(x^2 + bx + c = 0\) has **no integer roots**.
Promotional Banner

Topper's Solved these Questions

  • QUADRATIC EXPRESSIONS AND EQUATIONS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Chapter Test|50 Videos
  • QUADRATIC EXPRESSIONS AND EQUATIONS

    OBJECTIVE RD SHARMA ENGLISH|Exercise Section II - Assertion Reason Type|22 Videos
  • PROBABILITY

    OBJECTIVE RD SHARMA ENGLISH|Exercise Chapter Test|45 Videos
  • SEQUENCES AND SERIES

    OBJECTIVE RD SHARMA ENGLISH|Exercise Chapter Test|59 Videos

Similar Questions

Explore conceptually related problems

If p and q are odd integers, then the equation x^2+2px+2q=0 (A) has no integral root (B) has no rational root (C) has no irrational root (D) has no imaginary root

If a and b are the odd integers, then the roots of the equation, 2ax^2 + (2a + b)x + b = 0, a!=0 , will be

If a, b, c are odd integers, then the roots of ax^(2)+bx+c=0 , if real, cannot be

Let a, b and c be real numbers such that 4a + 2b + c = 0 and ab gt 0. Then the equation ax^(2) + bx + c = 0 has

If a, b and c are positive real and a = 2b + 3c , then the equation ax^(2) + bx + c = 0 has real roots for

If a ,b ,a n dc are odd integers, then prove that roots of a x^2+b x+c=0 cannot be rational.

If a + b + c = 0 then the quadratic equation 3ax^(2) + 2bx + c = 0 has

If 2a+3b+6c = 0, then show that the equation a x^2 + bx + c = 0 has atleast one real root between 0 to 1.

If 2a+3b+6c = 0, then show that the equation a x^2 + bx + c = 0 has atleast one real root between 0 to 1.

If a, b, c ∈ R, a ≠ 0 and the quadratic equation ax^2 + bx + c = 0 has no real root, then show that (a + b + c) c > 0

OBJECTIVE RD SHARMA ENGLISH-QUADRATIC EXPRESSIONS AND EQUATIONS -Exercise
  1. Let alpha,beta are the roots of x^2+b x+1=0. Then find the equation wh...

    Text Solution

    |

  2. The roots alpha, beta and gamma of an equation x^(3) - 3 a x^(2) + 3 b...

    Text Solution

    |

  3. If b and c are odd integers, then the equation x^2 + bx + c = 0 has-

    Text Solution

    |

  4. If the equations a x^2+b x+c=0 and x^3+3x^2+3x+2=0 have two common roo...

    Text Solution

    |

  5. If both the roots of the equation ax^(2) + bx + c = 0 are zero, then

    Text Solution

    |

  6. If alpha, beta , gamma, delta are the roots of the equation x^4+x^2+1=...

    Text Solution

    |

  7. The number of real roots of (x+1/x)^3+x+1/x=0 is

    Text Solution

    |

  8. The roots of the equation (3 - x)^(4) + (2 - x)^(4) = (5 - 2x)^(4) are

    Text Solution

    |

  9. The real roots of the equation |x|^3-3x^2+3|x|-2=0 are

    Text Solution

    |

  10. The number of positive integral roots of x^(4) + x^(3) - 4 x^(2) + x +...

    Text Solution

    |

  11. If x, y, z are real and distinct, then x^(2) + 4 y^(2) + x + 1 = 0, is

    Text Solution

    |

  12. The number of values of a for which equations x^3+a x+1=0 and x^4+a x^...

    Text Solution

    |

  13. For what value of m will the equation (x^2-bx)/(ax-c)=(m-1)/(m+1) hav...

    Text Solution

    |

  14. the values of a for which (a^2-1)x^2+2(a-1)x+2 is positive for all rea...

    Text Solution

    |

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

    Text Solution

    |

  16. If a, b, c are in A.P. and if (b-c)x^(2)++(c-a)x+a-b=0and2(c+a)x^(2)+(...

    Text Solution

    |

  17. If the expression [m x-1+(1//x)] is non-negative for all positive real...

    Text Solution

    |

  18. The set of values of p for which the roots of the equation 3x^(2)+2x+p...

    Text Solution

    |

  19. Let alpha and beta, be the roots of the equation x^2+x+1=0. The equati...

    Text Solution

    |

  20. If p and q are the roots of x^2 + px + q = 0, then find p.

    Text Solution

    |