Please Help! 10 Points +

Let the closed interval [a , b] be the domain of function f. the domain of f(x - 3) is given by (a) the open interval (a , b) (b) the closed interval [a , b] (c) the closed interval [a - 3 , b - 3] (d) the closed interval [a + 3 , b + 3]

What is the sum of these mixed numbers 2 1/8 + 4 3/8

If 10 men take 18 days to mow 60 acres of grass, how long will 15 men take to mow 80 acres?