Help me help me pls.

Afamily of five rents a kayak and splits the total time, k, equally. each family member spent less than 25 minutes kayaking. which values can be used to complete the math sentence below so that it accurately represents the situation? intro done

Complete the solution of the equation. find the value of y when x equals to 6 4x+y=20

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a