The greatest common factor using prime factorization for 28 and 63

How do i do this activity, is appreciated

Prove the divisibility of the following numbers: 25^9 + 5^7 is divisible by 30.also, read as (25 to the power of 9) + (5 to the power of 7) is divisible by 30. blank x 30what is the blank? ( it should be expressed in exponent form)

On the first of each month sasha runs a 5k race she keeps track of her times to track her progress her time in minutes is recorded in the table