Question

Tn+1=35-2Tn, T1=5 what is T20?

Answer 1

Answer:  3,495,265

Step-by-step explanation:

$T_{n+1}=35-2T_n\quad and\quad T_1=5, then\\T_{1+1}=35-2(T_1)\implies T_2=35-2(5)\implies T_2=25\\T_{2+1}=35-2(T_2)\implies T_3=35-2(25)\implies T_3=-15\\T_{3+1}=35-2(T_3)\implies T_4=35-2(-15)\implies T_4=65\\T_{4+1}=35-2(T_4)\implies T_5=35-2(65)\quad \implies T_5=-95\\T_{5+1}=35-2(T_5)\implies T_6=35-2(-95)\implies T_6=225\\.\qquad \qquad \qquad \qquad \qquad \qquad \downarrow\\.\qquad \qquad \qquad \qquad \qquad \qquad \downarrow\\.\qquad \qquad \qquad \qquad \qquad \qquad \downarrow$

$T_{18+1}=35-2(T_{18})\implies T_{19}=35-2(873,825)\implies T_{19}=-1,747,615\\T_{19+1}=35-2(T_{19})\implies T_{20}=35-2(-1,747,615)\implies T_{20}=3,495,265$