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Two candidates attempt to solve a quadra...

Two candidates attempt to solve a quadratic equation of the form `x^(2)+px+q=0`. One starts with a wrong value of p and finds the roots to be 2 and 6. the other starts with a wrong vlaue of q and finds the roots to be 2 and -9. find the correct roots and the equation.

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To solve the problem, we need to find the correct roots and the quadratic equation based on the information given about the roots found by the two candidates. ### Step-by-Step Solution: 1. **Identify the roots from the first candidate**: The first candidate finds the roots to be 2 and 6. - The sum of the roots \( S_1 = 2 + 6 = 8 \). - The product of the roots \( P_1 = 2 \times 6 = 12 \). 2. **Form the equation with the first candidate's roots**: The quadratic equation can be formed using the roots: \[ x^2 - S_1 x + P_1 = 0 \implies x^2 - 8x + 12 = 0 \] 3. **Identify the roots from the second candidate**: The second candidate finds the roots to be 2 and -9. - The sum of the roots \( S_2 = 2 + (-9) = -7 \). - The product of the roots \( P_2 = 2 \times (-9) = -18 \). 4. **Form the equation with the second candidate's roots**: The quadratic equation can be formed using the roots: \[ x^2 - S_2 x + P_2 = 0 \implies x^2 + 7x - 18 = 0 \] 5. **Set up the equations based on the candidates' findings**: - From the first candidate, we have \( p \) is incorrect, but \( q \) is correct. The correct \( q \) should be 12. - From the second candidate, \( q \) is incorrect, but \( p \) is correct. The correct \( p \) should be 7. 6. **Combine the information**: We have established that the correct quadratic equation is: \[ x^2 + 7x + 12 = 0 \] 7. **Find the correct roots**: To find the correct roots, we can factor the equation: \[ x^2 + 7x + 12 = (x + 3)(x + 4) = 0 \] Thus, the roots are: \[ x = -3 \quad \text{and} \quad x = -4 \] ### Final Answer: The correct roots of the quadratic equation are \( -3 \) and \( -4 \), and the correct equation is: \[ x^2 + 7x + 12 = 0 \]
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ICSE-QUADRATIC EQUATIONS-EXERCISE 10 (c)
  1. If the sum of the roots of the equation x^(2)-px+q=0 be m times their ...

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  2. If one root of the equation x^(2)+ax+8=0 is 4 while the equation x^(2)...

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  3. Find the value of a for which one root of the quadratic equation (a^(2...

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  4. If alpha,beta are the roots of the equation ax^(2)-bx+b=0, prove that ...

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  5. If alpha and beta are the roots of the equation x^(2)+x-7=0, form the ...

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  6. If alpha and beta are the roots of the equation 2x^(2)+3x+2=0, find th...

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  7. Find the equation whose roots are (alpha)/(beta) and (beta)/(alpha), w...

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  8. If alpha and beta are the roots of the equation 2x^(2)-3x+1=0, form th...

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  9. If a ne b and a^(2)=5a-3,b^(2)=5b-3, then form that equation whose roo...

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  10. Given that alpha and beta are the roots of the equation x^(2)=x+7. (...

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  11. Given that alpha and beta are the roots of the equation x^(2)-x+7=0, f...

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  12. Given that alpha and beta are the roots of the equation 2x^(2)-3x+4=0,...

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  13. The roots of the quadratic equation x^(2)+px+8=0 are alpha and beta. ...

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  14. If the roots of x^(2)-bx+c=0 be two consecutive integers, then find th...

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  15. The roots of the equation px^(2)-2(p+1)x+3p=0 are alpha and beta. If a...

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  16. The roots of the equation ax^(2)+bx+c=0 are alpha and beta. Form the q...

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  17. Two candidates attempt to solve a quadratic equation of the form x^(2)...

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  18. Given that alpha and beta are the roots of the equation x^(2)=7x+4, ...

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  19. The ratio of the roots of the equation x^(2)+alphax+alpha+2=0 is 2. fi...

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  20. If (1-p) is a root of the quadratic equation x^(2)+px+(1-p)=0, then it...

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