(4n⁴-8n+4) - (8n²+4n⁴+1)
How do I simplify this expression?

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

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?

I'm confused on this could anyone me and show me what i need to do to solve it.