Question

A(n)=-5*2^n-1 i dont know the geometric sequences i need the first, fourth and eighth terms of the sequence

Answer 1

$\bf A(n)=5\cdot 2^{n-1}\qquad \qquad \begin{array}{llll} 4th~term\\ 5\cdot 2^{4-1}\implies 5\cdot 2^3\implies 5\cdot 8\implies 40 \\\\\\ 8th~term\\ 5\cdot 2^{8-1}\implies 5\cdot 2^7\implies 5\cdot 128\implies 640 \end{array}$