Gabriela forgot to charge her phone after using it at the amusement park, and she didn't have her charger with her. Her battery drained at a constant rate. The power level of the battery, y, after x minutes is y=−0.5x+72. What do the slope and y-intercept represent in this situation? Write 2 to 3 sentences explaining how the slope and y-intercept are related to the cell phone battery. Be sure to use clear math language in your explanation.

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