Addmaths question(logarithm)

Question

(7²⁰²⁴+7²⁰²³)/7^x=8         Find the value of x.

My working:

 (7²⁰²⁴+7²⁰²³) / 7^x = 8 

7²⁰²⁴+7²⁰²³ = 8(7^x)

lg (7²⁰²⁴+7²⁰²³) = lg 8 + x lg 7

How do I continue?I am stuck at this "lg (7²⁰²⁴+7²⁰²³) "

* I know how to use google myself,or use some math solver tools online.But both of them can't solve such a question because 7²⁰²⁴ exceed the format of x⁹⁹(same as our scientific calculator).

Answer 1

 This is my first answer after creating this account.  Please let me know if you can see the attached photo.  I hope this is not too late. 

Comments

Thanks the answer is correct :)
Thanks for the working!

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whew I feel shameful to forgot about the basic law of indices......

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It is ok.  Always remember big number (in this case, the index) , it is very likely that we just need to simplify (finding common base or common factor). Don't really need to calculate because it is impossible to calculate ourselves (with calculators or working ourselves).

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Welcome