# How can I solve 7x≡5 (mod 11)?

The question also asks to use trial and error to find 7^-1 (mod 11)

### 2 Answers

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- AmyLv 74 weeks ago
Are you supposed to use trial and error on the first problem too?

The numbers that equal 5 mod 11 are 5, 16, 27, ...

If you keep adding 11, eventually you'll reach a multiple of 7.

7^-1 is the number that when multiplied by 7 makes 1.

7x ≡ 1 (mod 11)

- billrussell42Lv 74 weeks ago
5 mod 11 (5 base 11) = 5

7x = 5

x = 7/5

7 base 11 = 7

1/7 = 0.1428571 base 10 or 0.163163 base 11

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