Which sentence describes a benefit that short-term disability insurance offers a policyholder?

Given that (x-3) is a factor of f(x)=x^3+ax^2-x-6, find a and hence the number of real roots or the equation f(x)=0

Find three consecutive numbers such that the sum of one-fourth the first and one-fifth the second is five less than one-seventh the third

Me. i can't figure out this question. give an explanation too. .