Let $t=2s-s^2$ and $s=n^2 - 2^n+1$. What is the value of $t$ when $n=3$?
To find the value of $t$ when $n=3$, I need to first substitute $n=3$ into the expression for $s$ and simplify. So $s=3^2-2^3+1=9-8+1=2$. Now that I have the value of $s$, I can plug it into the expression for $t$ and simplify. So $t=2s-s^2=2(2)-(2)^2=4-4=0$. 