How do you insert parentheses to make #3^2-9*2+1=8# true?
Parentheses are the ultimate defining mark for algebraic order of operations. Their proper use removes all ambiguity in the order in which a series of operations should take place. So, the solution is just to define the correct order of combination to arrive at the desired value of 8 at the end.
So, a final "parenthetical" order could be: