If -5 is a root of a quadratic equation 2 X square + P x - 15 equal to zero and the quad equation P X square + PX + K equal to zero has equal roots find the value of k
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Answer:
What is the condition for both roots equal in two different quadratic equation? ( look que. No.10. How we gotta know that both roots are equal.)
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I think the wording on this question is misleading. I do not believe that the question is suggesting that there is a quadratic with a double root, either the 1st quadratic or the second quadratic. Instead it is my belief that the question is suggesting that the 1st quadratic, x^2+2x+3=0 and the second quadratic, ax^2 +bx +c=0 share at least one root between the two different equations. Using the quadratic formula reveals that the answers to the 1st quadratic are -1 + i(radical two) and -1 - i(radical two) because complex solutions always come in conjugate pairs, both equations must share not just one solution, but both solutions. As a result the second equation is just the 1st equation multiplied by some constant value, say 3 for example. Which would make the new second equation 3x^2+6x+9=0. Regardless of the constant value selected the 2nd equation will have the coefficients a,b, and c in the same proportion as the the known equation.
This means the new equation has a, b, and c in a 1:2:3 proportion, which is choice (1).