question 16 to 19please type it out the answer or if has an option type it out the correct option.

Question 16 (2 points) A force of 10 lb is required to hold a spring stretched 4 in. beyond its natural length. How much work (in pound-inches) is done in stretching it from its natural length to 9 in. beyond its natural length? Question 17 (2 points) Find the work done in pushing a car a distance of 12 m while exerting a constant force of 300 N. Question 18 (2 points) If 132 J of work are needed to stretch a spring from 9 cm to 12 cm and another 588 J are needed to stretch it from 12 cm to 19 cm, what is the natural length of the spring? Select the correct answer. ( 1) 6 cm O 2) 5 cm ( 3) 3 cm ( 4) 4 cm ( 5) 1 cm Question 19 (2 points) Find the number(s) a such that the average value of the function f(x) = 80 - 34x + 3x2 on the interval [0, a] is equal to 10. Select all that apply. O 1) d = 8 O 2) a = 10 0 3) a = 7 0 4) a =-7 0 5) a =-10