if alpha and beta are zeros of the polynomial p(x)=3x^2-5x+6 find alpha^3+beta^3
Answers
Answered by
27
3x²-5x+6
α+β=5/3
αβ=6/3=2
α³+β³=(α+β)³-3αβ(α+β)
=(5/3)³-3×2×5/3
=125/27-10
=125-270/10
=-14.5
α+β=5/3
αβ=6/3=2
α³+β³=(α+β)³-3αβ(α+β)
=(5/3)³-3×2×5/3
=125/27-10
=125-270/10
=-14.5
Answered by
34
The given polynomial is
p (x) = 3x² - 5x + 6
Since α and β are the zeros of p (x),
α + β = - (- 5)/3
⇒ α + β = 5/3 ...(i)
and
αβ = 6/3
⇒ αβ = 2 ...(ii)
Now, α³ + β³
= (α + β)³ - 3αβ (α + β)
= (5/3)³ - (3 × 2 × 5/3)
= 125/27 - 10
= (125 - 270)/27
= - 145/27
#
Similar questions