To find the answers, you basically have to use trial and error. I'm not sure how else to find them.
Anyways, grouping up "6+12" as one group and "2^2-2+1" as the other leads to
[tex](6+12) \div (2^2-2+1) = 18 \div 3 = 6[/tex]
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For the next problem, you'll need 2 sets of parenthesis, but this time one set of parenthesis is inside another one. The (6+12) becomes 18, which divides by 2 to get 9. Squaring that leads to 81 and then you subtract off 1 to get 80.
[tex]( (6+12) \div 2)^2 - 2 + 1 = (18\div 2)^2 - 1 = 9^2-1 = 81-1 = 80[/tex]
