How do you insert parentheses to make 3^2-9*2+1=8 true?

Jan 11, 2018

$9 - \left(9 \times 2\right) + 1 = - 8$

Explanation:

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.
${3}^{2}$ is already a value, so just convert it: $9$.

$9 - 9 \times 2 + 1 = 8$ We can't combine the first two terms, because they become 0. 2 + 1 x 9 is way beyond the desired final value. So combine the middle ones first.
$9 - \left(9 \times 2\right) + 1 = 8$ ; $9 - 18 + 1 = 8$ Now it doesn't matter what the order is, although we end up with a -8 instead of +8, which looks like an error in the problem statement.
So, a final "parenthetical" order could be:
$9 - \left(9 \times 2\right) + 1 = - 8$