(c+4)^2(4-c)^2 i need help

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Robin spent 25% more time on his research project than he had planned he’s been an extra h ours on the project which of the following expressions could represent the number of hours rob actually spent on the project

As a self-employed seamstress, you know that it takes 7 yards of material to make 3 jackets. you bought 15 yards of material to make 7 jackets. did you buy enough material? if not, how much were you over or under?