I am trying to figure out how to simply a canonical sum of products expression that is from this expression: $$ f_1(x_1,x_2,x_3) = \sum m (2,3,4,6,7) $$ where m is canonical minterms
I got: $$ \bar{x}_{1}x_2\bar{x}_3 + \bar{x}_{1}x_2x_3+x_1\bar{x}_{2}\bar{x}_{3}+x_1x_2\bar{x}_{3} + x_1x_2x_3 $$
then I simplify and get: $$ x_2+x_1x_2 $$
which is incorrect. I the answer in the book is: $$ x_2+x_1\bar{x}_{3} $$