A sequence x1,x2,x3,… x_1, x_2, x_3, \dots\,x1,x2,x3,… is defined by
x1=axn=3xn−1+2,n≥2 \begin{aligned}x_1 &= a \\x_n &= 3x_{n-1} + 2, \quad n \geq 2\end{aligned} x1xn=a=3xn−1+2,n≥2Find an expression for x2 x_2\,x2 in terms of aaa.
Show that x3=9a+8x_3 = 9a + 8x3=9a+8.
Find ∑r=14xr\sum_{r=1}^4 x_r∑r=14xr in terms of aaa.
