A question about fractions and I need working out its all of part 1

A) The student has simply added the two numerators and the two denominators together. This is incorrect. In order to add two fractions together, you must use multiplication or division to ensure both denominators are the same.

b)

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?