SOLUTION: One root of the equation 2x^3 – 5x^2 – 8x + d = 0 is the negative of another. Compute d. (A) –10 (B) –4 (C) 8 (D) 20 (E) 24

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: One root of the equation 2x^3 – 5x^2 – 8x + d = 0 is the negative of another. Compute d. (A) –10 (B) –4 (C) 8 (D) 20 (E) 24      Log On


   

Question 323158: One root of the equation 2x^3 – 5x^2 – 8x + d = 0 is the negative of another. Compute d.
(A) –10 (B) –4 (C) 8 (D) 20 (E) 24
Answer by Jk22(389) About Me  (Show Source):
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(D) d=20
2(x^2-a^2)(x+b)=2x^3+2bx^2-2a^2x-2a^2b
b=-5/2, a=2, d=-2a^2b=20