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If p != 0, q != 0 and the roots of x^(2)...

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

A

(1, -2)

B

(1, 1)

C

(2, -2)

D

(-1, 2)

Text Solution

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The correct Answer is:
To solve the problem, we need to find the values of \( p \) and \( q \) given that the roots of the quadratic equation \( x^2 + px + q = 0 \) are \( p \) and \( q \). ### Step-by-Step Solution: 1. **Identify the Roots**: The roots of the quadratic equation \( x^2 + px + q = 0 \) are given as \( p \) and \( q \). 2. **Use the Sum of Roots**: According to Vieta's formulas, the sum of the roots \( p + q \) is equal to \( -\frac{\text{coefficient of } x}{\text{coefficient of } x^2} \). Thus, \[ p + q = -p \quad \text{(Equation 1)} \] 3. **Use the Product of Roots**: Similarly, the product of the roots \( pq \) is equal to \( \frac{\text{constant term}}{\text{coefficient of } x^2} \). Therefore, \[ pq = q \quad \text{(Equation 2)} \] 4. **Substituting Equation 1 into Equation 2**: From Equation 1, we can express \( q \) in terms of \( p \): \[ q = -p - p = -2p \] Now substitute this value of \( q \) into Equation 2: \[ p(-2p) = -2p \] Simplifying this gives: \[ -2p^2 = -2p \] 5. **Rearranging the Equation**: We can rearrange the equation: \[ -2p^2 + 2p = 0 \] Factoring out \( -2p \): \[ -2p(p - 1) = 0 \] 6. **Finding the Values of \( p \)**: This gives us two possible solutions: \[ p = 0 \quad \text{or} \quad p = 1 \] Since \( p \neq 0 \) (as given in the problem), we have: \[ p = 1 \] 7. **Finding the Value of \( q \)**: Now substituting \( p = 1 \) back into the expression for \( q \): \[ q = -2p = -2(1) = -2 \] 8. **Final Result**: Thus, the values of \( (p, q) \) are: \[ (p, q) = (1, -2) \] ### Summary: The final answer is \( (p, q) = (1, -2) \).
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