Home
Class 12
MATHS
If p is a prime and both roots of x^(2)-...

If p is a prime and both roots of `x^(2)-px-444p=0` are integers, then p is equal to

A

2

B

3

C

37

D

none of these

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to determine the value of the prime number \( p \) such that both roots of the quadratic equation \( x^2 - px - 444p = 0 \) are integers. ### Step-by-Step Solution 1. **Identify the Quadratic Equation**: The given quadratic equation is: \[ x^2 - px - 444p = 0 \] 2. **Calculate the Discriminant**: The discriminant \( D \) of a quadratic equation \( ax^2 + bx + c = 0 \) is given by: \[ D = b^2 - 4ac \] Here, \( a = 1 \), \( b = -p \), and \( c = -444p \). Thus, \[ D = (-p)^2 - 4 \cdot 1 \cdot (-444p) = p^2 + 1776p \] 3. **Set the Discriminant as a Perfect Square**: For the roots to be integers, the discriminant must be a perfect square: \[ D = p^2 + 1776p = k^2 \quad \text{for some integer } k \] Rearranging gives: \[ p^2 + 1776p - k^2 = 0 \] 4. **Factor the Quadratic**: The discriminant \( D \) must be a perfect square, so we can express it as: \[ D = p(p + 1776) \] We need \( p(p + 1776) \) to be a perfect square. 5. **Analyze the Expression**: Since \( p \) is a prime number, we will test small prime numbers to see if \( p(p + 1776) \) is a perfect square. 6. **Testing Values of \( p \)**: - For \( p = 2 \): \[ D = 2(2 + 1776) = 2 \times 1778 = 3556 \quad \text{(not a perfect square)} \] - For \( p = 3 \): \[ D = 3(3 + 1776) = 3 \times 1779 = 5337 \quad \text{(not a perfect square)} \] - For \( p = 5 \): \[ D = 5(5 + 1776) = 5 \times 1781 = 8905 \quad \text{(not a perfect square)} \] - For \( p = 7 \): \[ D = 7(7 + 1776) = 7 \times 1783 = 12481 \quad \text{(not a perfect square)} \] - For \( p = 37 \): \[ D = 37(37 + 1776) = 37 \times 1813 = 67181 \] We check if \( 67181 \) is a perfect square: \[ \sqrt{67181} = 259 \quad \text{(which is an integer)} \] 7. **Conclusion**: Since \( D \) is a perfect square when \( p = 37 \) and \( p \) is a prime number, we conclude: \[ p = 37 \] ### Final Answer: The value of \( p \) is \( \boxed{37} \).
Promotional Banner

Similar Questions

Explore conceptually related problems

If p != 0, q != 0 and the roots of x^(2) + px +q = 0 are p and q, then (p, q) =

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

If -1 and 3 are the roots of x^(2)+px+q=0 , find the values of p and q.

If sin theta, cos theta are the roots of 6x^(2)-px+1=0 , then p^(2) =

Let f(x) = [ n + p sin x], x in (0,pi), n in Z , p is a prime number and [x] = the greatest integer less than or equal to x. The number of points at which f(x) is not not differentiable is :

int_(-pi)^(pi) [cos px-sin qx]^(2) dx where p,q are integers is equal to

If alpha, beta be the roots of the equation x^2-px+q=0 then find the equation whose roots are q/(p-alpha) and q/(p-beta)

If a+b+c=0 , prove that the roots of ax^(2)+bx+c=0 are rational. Hence, show that the roots of (p+q)x^(2)-2px+(p-q)=0 are rational.

IF the different between the roots of x^(2) -px+q=0 is 2, then the relation between p , and q is

If 3+4i is a root of equation x^(2)+px+q=0 where p, q in R then