5. Determine whether the relation is a function: a. {(- 3, -3), (-2, -2), (-1, -1), (0,0)} b. {(1, 2), ( 3, 4 ), (6, 5), (8,5 ) } c. {(1, 2), (3, 4), (5, 6), (5, 8) } 6. For each pair of functions, find (f . g) (x) and the domain of (f . g) (x) in interval notation. a) f(x) = 5x + 6 and g(x) = 2x2 -x -1 b) f (x) = x+2 and g(x) =; c) f(x) = V10 -x and g(x) = 2x + 14. 7. Find each function (f-g)(x), (fg)(x), (f/g)(x), and determine their domain in interval notation. a. f(x) = 2x2 -x -3 and g(x) = x+1 b. f (x) = 5x - 3x2, g(x) = 4x c. f(x) = 5-x, 9(x) = x+ 10