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Cubic equations: roots in arithmetic progression

mathematical
The equation 2x3−9x2+kx−6=02x^3 - 9x^2 + kx - 6 = 0 has three real roots that form an arithmetic sequence.
Facts you may need
  • For 2x3−9x2+kx−62x^3 - 9x^2 + kx - 6: sum of roots =92= \frac92, product =3= 3 — Vieta's formulas.
  • Factor theorem — A known root gives a linear factor.

(a)

Find the value of kk.

(b)

Find the three roots.