Your friend says that 1/2 + 1/7 is equal to 2/14 . Is this correct ? not , what mistake did your friend make?

It’s not correct.

1/2 + 1/7 = 9/14

1 x 7 / 2 x 7 + 1 x 2 / 7 x2
= =
7/14 + 2/14

7 + 2 = 9 so it’s 9/14

Don’t need to change the denominators now that they are the same.

Your friend didn’t change it so that the denominators were the same on each fraction and multiplied the two numerators and denominators before changing it that’s where they made the mistake.

Ibelieve the answer is c