Suzanna wants to measure a board, but she doesn't have a ruler to measure with. However, she does have several copies of a book that she knows is 17 centimeters long. Suzanna lays the books end to end and finds that the board is the same length as 21 books. How many centimeters long is the board?
Suzanna needs a board that is at least 3.5 meters long. Is the board long enough? Explain.

there are no short passages to look at

idk

step-by-step 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