15 16 A 30-pound force will stretch the spring in. 18. Solve the equation. x3/7 -8 The solution set.

15 16 A 30-pound force will stretch the spring in. 18. Solve the equation. x3/7 -8 The solution set is (Use a comma to separate answers as needed.) 19. Use the properties of logarithms to rewrite the following expression as a sum or difference of logarithms each of which is the logarithm of an integer or a variable. Assume all variables represent positive real numbers. 5x log102 5x 10910 20. Suppose an Egyptian mummy is discovered in which the amount of carbon-14 present is only about two-sevenths the amount found in living human beings. The amount of carbon-14 present in animal bones after t years is given by yaYo -0.0001216, where yo is the amount of carbon-14 present in living human beings. About how long ago did the Egyptian die? About yr ago the Egyptian had died. (Round to the nearest integer as needed.)