Which situation results in a final value of exactly zero? a the temperature outside was 15 degrees below 0 at 7: 00 a. m. the temperature rose 3 degrees each of the next 4 hours. b hector earned $7: 40 for each of 8 hours of work. he used $60 of this money to buy video games. c mrs. kaplan received an order to bake 120 cookies. she completed the order by baking 24 cookies every 30 minutes over a period of 5 hours. d a runner ran up hill during 2.4 minutes at a rate of 30 feet per minute. the runner ran downhill diring 1.2 minutes at a rate of 15 feet per minute.

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places

49/6 is going to equal 8 1/6