How (-1) mod 5 is equal to 9?

-1(mod 5)

The positive value added will be the new number .

see below

Step-by-step explanation:

when we say a≡b mod c

it means that c divides a-b

or that b is the remainder of a/c

so 9/5 the remainder is 4

so we have

9≡4 mod 5

we can substract 5 from both sides and the equation will still be true

9-5≡4-5 mod 5

4≡1 mod 5

if we do it by c divides a-b

5 divides 9-(-1)

5 divides 10

which is true so

9≡-1 mod 5

why can't you?

step-by-step explanation:

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step-by-step explanation: