For this case we have the following equation:

Where,
w: The weight of a spring in pounds
E: the energy stored by the spring in joules.
Substituting values we have:

Making the corresponding calculation:
Answer:
the approximate weight of the spring in pounds is:
2x² - 15x + 7
(2x - 1)(2x-14)
(2x - 1)(x - 7) x= 1/2 or 7
Answer: i dont this you can combine like terms for this question because none of these have the same variable or anything.
Answer:
To find the average rate of change, we divide the change in the output value by the change in the input value. The Greek letter Δ (delta) signifies the change in a quantity; we read the ratio as “delta-y over delta-x” or “the change in y divided by the change in x”.
To do these problems, you plug in the ‘n’ value given into the equation.
a. 6j - 3 : j = 4
6(4) - 3
24 - 3
21
b. 1/2b + 5 : b = 14
1/2(14) + 5
7 + 5
12
c. 8 + 4k : k = 3.5
8 + 4(3.5)
8 + 14
22