Question

zn = 5 - n^2, cn = n,^2 + 15, найди значение выражения Зz2 + 2с3.
Ответ:​

Answer 1

$\displaystyle\bf\\Z_{n} =5-n^{3} \\\\C_{n} =n^{2} +15\\\\\\3Z_{2} +2C_{3} =3\cdot\Big(5-2^{3} \Big)+2\cdot\Big(3^{2} +15\Big)=3\cdot\Big(5-8\Big)+2\cdot\Big(9+15\Big)=\\\\\\=3\cdot(-3)+2\cdot 24=-9+48=39\\\\\\Otvet:39$