web2.0calc
 
+0  
 

 I still need help

+1
771
7
avatar+479 

Without using a calculator, find the largest prime divisor of 5^12 minus 2 times 10^6 plus 2^12.

 Jul 14, 2020

7+0 Answers

 #1
avatar
+2

625  x   625  x  625 =244,140,625

 

244,140,625  - [2 x 1,000,000] =242,140,625

 

2^4  x  2^4  x  2^4 =16  x  16  x 16 =4,096

 

242,140,625  +  4,096 =242,144,721

 

242,144,721  = 7 x 7 x 9 x 9 x 13 x 13 x 19 x 19

 

The largest prime divisor = 19

 Jul 15, 2020
 #2
avatar+479 
0

Thanks........ but I don't think that's correct. 

 Jul 15, 2020
 #3
avatar+33652 
+2

Why don't you think that's correct?

 

Here's another way of doing it:

 

Clearly, 19 is the largest prime factor.

Alan  Jul 15, 2020
 #4
avatar+479 
+1

Ohhh that makes more sense!

I thought it was a bit low...

Tysm!!!

HelpBot  Jul 15, 2020
 #5
avatar+118690 
-1

Next time please add the explanation of why you think whatever you think. 

(I mean right from the beginning)

People like feedback.

If you think an answer is not right, or you have doubts, you should explain what those doubts are.

Melody  Jul 17, 2020
edited by Melody  Jul 17, 2020
 #6
avatar+118690 
-1

Thanks guest and Alan for your explanations   laugh

Melody  Jul 17, 2020
 #7
avatar+479 
0

Okay, thanks!

HelpBot  Jul 17, 2020

1 Online Users

avatar

Top Users

avatar+130081 CPhill moderator
avatar+37158 ElectricPavlov
avatar+15001 asinus moderator
avatar+3146 admin administrator
avatar+2717 LiIIiam0216
avatar+2539 GingerAle
avatar+2499 Solveit
avatar+1944 NotThatSmart
avatar+1927 tomtom
avatar+1770 bader
avatar+1577 parmen

Sticky Topics