Jump to content
  • Advertisement
Sign in to follow this  
subflood

solving for x and y exponent

This topic is 5039 days old which is more than the 365 day threshold we allow for new replies. Please post a new topic.

If you intended to correct an error in the post then please contact us.

Recommended Posts

here it goes: 2^4 x 3^5 x 4^3 = 2^x x 3^y what is value of x + y I'm not sure how I can get this. The 4^3 confuses me. Thanks for the help.

Share this post


Link to post
Share on other sites
Advertisement
Guest Anonymous Poster
Quote:
Original post by subflood
but I'm not sure why. I just took the hint and worked from there but I don't get why that works.

well it's 24 x 35 x 43
43 can be substituted with (22)3.
According to the arithmetic rules of powers you get 22 x 3, which equals 26.

Now following the next rule you can multiply 24 and 26 by adding the exponents to get 210.

The final equation thus is 210 x 35 = 2x x 3y.

Trivial - you don't have to do a thing, except replacing 'x' and 'y' with their literal counterparts from the left side of the equation [smile].

Share this post


Link to post
Share on other sites
Quote:
Original post by subflood
but I'm not sure why. I just took the hint and worked from there but I don't get why that works.

well it's 24 x 35 x 43
43 can be substituted with (22)3.
According to the arithmetic rules of powers you get 22 x 3, which equals 26.

Now following the next rule you can multiply 24 and 26 by adding the exponents to get 210.

The final equation thus is 210 x 35 = 2x x 3y.

Trivial - you don't have to do a thing, except replacing 'x' and 'y' with their literal counterparts from the left side of the equation [smile].

[edit] Above AP was me, too. [/edit]

Share this post


Link to post
Share on other sites
It would be far less trivial to actually prove this (x,y) solution is unique. If it's not the case you can't tell what x+y is. ;)

Share this post


Link to post
Share on other sites
Guest Anonymous Poster
Quote:
Original post by darookie

The final equation thus is 210 x 35 = 2x x 3y.

Trivial - you don't have to do a thing, except replacing 'x' and 'y' with their literal counterparts from the left side of the equation [smile].


Actually that's wrong. The solution for x is:

x = log_2(1024 * 3^(5-y))

For example if you take y = 5 then you have the answer you arrived at: x = 10. But if you take y = 6 then x = 10 - log_2(3), for y = 7, x = log_2(1024/9) and so on.

Share this post


Link to post
Share on other sites
Sign in to follow this  

  • Advertisement
×

Important Information

By using GameDev.net, you agree to our community Guidelines, Terms of Use, and Privacy Policy.

We are the game development community.

Whether you are an indie, hobbyist, AAA developer, or just trying to learn, GameDev.net is the place for you to learn, share, and connect with the games industry. Learn more About Us or sign up!

Sign me up!