To find the value of α15+β15+α10+β10α23+β23+α14+β14,
Let an=αn+βn
Hence,
α15+β15+α10+β10α23+β23+α14+β14=a15+a10a23+a14
Now, x2+6x+3=0 has roots α and β
So, x=2−6±−6
⇒x=6(2−1±i)
⇒x=3(2−1±i)
Hence, α=3e4i3π and β=3e4i5π
Now, solving α15+β15+α10+β10α23+β23+α14+β14
=(3)15ei15×43π+ei15×45π+(3)10ei10×43π+ei×10×45π(3)23ei23×43π+ei23×45π+(3)14ei14×43π+ei14×45π
=(3)4(3)5ei15×43π+ei15×45π+ei10×43π+ei×10×45π(3)9ei23×43π+ei23×45π+ei14×43π+ei14×45π
=9×(3)5(21+i−1+i)+0(3)9(21+i−1+i)+0\left\{\text{as}{e}^{i\dfrac{21\pi}{2}} + {e}^{i\dfrac{35\pi}{2}} = 0 + isin\dfrac{21\pi}{2} + 0 + isin\dfrac{35\pi}{2} = i - i = 0\right\}</p><p>= 9 \times \left(\dfrac{{\left(\sqrt{3}\right)}^{9}\left(\dfrac{2i}{\sqrt{2}}\right)}{{\left(\sqrt{3}\right)}^{5}\left(\dfrac{2i}{\sqrt{2}}\right)}\right)</p><p>= 9 \times {\left(\sqrt{3}\right)}^{4}</p><p>= 81