Posted by **Francesca** on Tuesday, October 11, 2011 at 7:55pm.

Find the value of x:

20x ≡ 9 (mod 15)

- Math -
**Steve**, Wednesday, October 12, 2011 at 4:58am
Let x=1

20 ≡ 5 (mod 15)

As x increases by 1, the residue increases by 5, so no integer value of x satisfies the equation.

If you allow rational values for x, then it is easy to find many such x's: 9/20 comes to mind first...

## Answer This Question

## Related Questions

- math - Which two is true as i'm confused A) 3+7 ß 10 mod 15 17 + 9 ß 4 mod 21 ...
- Math - Which Statements of congruence are true and which are false and why? 177 ...
- math - Which Statements of congruence are true and which are false and why? 177 ...
- Math - Which Statements of congruence are true and which are false and why? 177 ...
- Math - Find all numbers $r$ for which the system of congruences: x == r mod 6 x...
- math - how do we find the least residue of 1789 (mod 4), (mod 10), (mod 101)
- math - how do we find the least residue of 1789 (mod 4), (mod 10), (mod 101)
- DISCRETE MATHS - Prove that if n is an odd positive integer, then 1 ≡ n2 (...
- Discrete Mathematics - Prove that if n is an odd positive integer, then 1 ≡...
- Math - Using 10^n = x (mod 9). Given that d=2935107 =2*10^6 + 9*10^5 + 3*10^4 + ...

More Related Questions