Need someone to check my work again

[abel muroi]

I was given the problem 4(1 + 10^5x) = 9 and was told to solve for x

here is my work..

4(1 + 10^5x) = 9 ((first i divide both sides by 4))

1 + 10^5x = 9/4 ((then i subtract 1 from both sides))

10^5x = 5/4 ((then i take the log of both sides))

(5x) log 10 = log 5/4 ((i divided both sides by log 10))

5x = 0.096910013 ((i divide both sides by 5))

x = 0.019382003

did i do this correctly?

 

[Steven G]

I was given the problem 4(1 + 10^5x) = 9 and was told to solve for x

here is my work..

4(1 + 10^5x) = 9 ((first i divide both sides by 4))

1 + 10^5x = 9/4 ((then i subtract 1 from both sides))

10^5x = 5/4 ((then i take the log of both sides))

(5x) log 10 = log 5/4 ((i divided both sides by log 10))

5x = 0.096910013 ((i divide both sides by 5))

x = 0.019382003

did i do this correctly?

You are correct. Good job! But why bother us when you can plug in the value for x on the left hand side of the equation and see if you get 9?

 

[stapel]

...why bother us when you can plug in the value for x on the left hand side of the equation and see if you get 9?

Just to clarify, the original poster is not being regarded as having been "annoying" anybody. The previous reply is meant as a humorous way of pointing out a very good way of checking one's own work, something which can be an absolute lifesaver on tests!