Please, please help me, Answer it correctly and properly. Thank you in advance!

Write the letters if it is a function.

How do you multiply a mixed fraction by a regular fraction

Can someone answer this question? : )

If the ratio of sum of the first m and n terms of an ap is m2 : n2 , show that the ratio of its mth and nth terms is (2m − 1) : (2n − 1).