What are three equal ratios to 5: 8

Aparallel system functions whenever at least one of its components works. consider a parallel system of n components, and suppose each component works independently with probability 0.5. find the conditional probability that component n works given that the system is working

If given an equation of a line such as -1/2x+6 how would you create an equation of a line parallel and perpendicula to this line that goes through another point such as (4,10)

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