6. Let p be a prime number and k an integer such that x 2 + kx + p = 0 has two positive integer solutions. What is the value of k+ p? 1 O -1 O 2 O -2

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**Question 6: Quadratic Equation Problem**

Let \( p \) be a prime number and \( k \) an integer such that the quadratic equation \( x^2 + kx + p = 0 \) has two positive integer solutions. What is the value of \( k + p \)?

**Options:**

- ○ 1
- ○ -1
- ○ 0
- ○ 2
- ○ -2

**Solution Explanation:**

To solve this problem, we determine the conditions under which the quadratic equation has two positive integer solutions. The roots of the equation are solutions to:

\[ x^2 + kx + p = 0 \]

Using Vieta’s formulas, if the roots are \( r_1 \) and \( r_2 \), then:

1. The sum of the roots \( r_1 + r_2 = -k \)
2. The product of the roots \( r_1 \cdot r_2 = p \)

Since \( r_1 \) and \( r_2 \) are positive integers, and \( p \) is a prime number, the only possible values for \( r_1 \) and \( r_2 \) are \( 1 \) and \( p \), giving us:

\[ r_1 = 1, \, r_2 = p \quad \text{or} \quad r_1 = p, \, r_2 = 1 \]

In both scenarios, \( r_1 + r_2 = 1 + p \).

Thus:

\[ -k = 1 + p \Rightarrow k = -(1 + p) \]

To find \( k + p \):

\[ k + p = -(1 + p) + p = -1 \]

Hence, the correct answer is \(-1\).
Transcribed Image Text:**Question 6: Quadratic Equation Problem** Let \( p \) be a prime number and \( k \) an integer such that the quadratic equation \( x^2 + kx + p = 0 \) has two positive integer solutions. What is the value of \( k + p \)? **Options:** - ○ 1 - ○ -1 - ○ 0 - ○ 2 - ○ -2 **Solution Explanation:** To solve this problem, we determine the conditions under which the quadratic equation has two positive integer solutions. The roots of the equation are solutions to: \[ x^2 + kx + p = 0 \] Using Vieta’s formulas, if the roots are \( r_1 \) and \( r_2 \), then: 1. The sum of the roots \( r_1 + r_2 = -k \) 2. The product of the roots \( r_1 \cdot r_2 = p \) Since \( r_1 \) and \( r_2 \) are positive integers, and \( p \) is a prime number, the only possible values for \( r_1 \) and \( r_2 \) are \( 1 \) and \( p \), giving us: \[ r_1 = 1, \, r_2 = p \quad \text{or} \quad r_1 = p, \, r_2 = 1 \] In both scenarios, \( r_1 + r_2 = 1 + p \). Thus: \[ -k = 1 + p \Rightarrow k = -(1 + p) \] To find \( k + p \): \[ k + p = -(1 + p) + p = -1 \] Hence, the correct answer is \(-1\).
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