Solve for "a" in Polynomial Function: 2x^3 - ax^2 - 12x - 7

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The discussion focuses on determining the value of "a" in the polynomial function 2x^3 - ax^2 - 12x - 7, such that the function has a repeated factor. The solution involves expressing the polynomial as (x-b)^2(2x-c) and comparing coefficients, leading to three equations. By analyzing the derivative 2(3x^2 - ax - 6), it is established that setting a = 3 yields a double root at x = -1, confirming that the polynomial can be factored as 2(x + 1)^2(x - 7/2).

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Could someone please help me with this question, I'd be most obliged:

Q) Find the value of "a" for which the function
2x^3 - ax^2 - 12x - 7
has a repeated factor.

Thanks
 
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If you mean two identical roots, then ...

write 2x^3 - ax^2 - 12x - 7 = (x-b)^2(2x-c)

Expand the RHS and compare coefficients. You have 3 equations in 3 unknowns.
 
Since we are seeking only a specific solution, we can keep in mind that if the cubic has a double root, that this root is also present in its derative. The derative is: 2(3X^2-aX-6). Here if we let a =3, we get X =2, -1. -1 works in the original equation and the factoring then is 2(x+l)^2(x-7/2).
 

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