How do we do this problem 3(b3-5)

What would be the reasons for lines 3 and 4? a. addition property; subtraction property b. addition property; solve c. substitution property; subtraction property d. substitution property; prove

There were 25 students who answered to a survey about sports. four-fifths of them like football. how many students like football?

Here is another math questions. i will keep asking different questions. 4^2x=6