To solve this expression, we need to find a common denominator for the fractions involved. The common denominator for 7, 14, and 2 is 14.

1/7 can be written as 2/14.
-3/14 remains the same.
1/2 can be written as 7/14.

Now we can rewrite the expression:

2/14 - (-3/14) + 7/14

To subtract a negative fraction, we can change the subtraction to addition and change the sign of the fraction being subtracted:

2/14 + 3/14 + 7/14

Now we can add the fractions:

(2 + 3 + 7)/14

12/14

Simplifying the fraction by dividing both the numerator and denominator by their greatest common divisor, which is 2:

6/7

Therefore, 1/7 - (-3/14) + 1/2 equals 6/7.