After john worked at a job for 10 years, his salary doubled. if he started at $x, his salary after 10 years is

After ten years his salary is x2

Step-by-step explanation:

John’s salary after doubling in 10 years is $ 2x

Solution:

It is given to us that John worked at a job for 10 years.

He started working at the job with a salary of $x.

After 10 years the salary has been doubled.

We have been asked to find John’s salary now after doubling.

To find John’s salary after 10 years we need to do the following.

Salary after 10 years = Salary before 10 years 2

Therefore, John’s salary after doubling in 10 years is $2x

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