Find the least common multiple of x2 – 2x – 15 and x2 + 2x – 3.

(x + 5)(x + 3)(x + 1)
(x – 5)(x + 1)(x + 3)
(x – 5)(x + 3)(x – 1)
(x + 3)(x – 1)(x + 5)
z varies inversely with the product of x and y. When x = 2 and y = 4, z = 0.5

What is the value of z when x = 4 and y = 9?

40
1/9
45/2
40/9