well, 987*7 = 6909 = 11*628 + 1
not sure what you mean by inverse, but x=7 is a solution to the equation.
What is the inverse of 987x=1 (mod 11)?
What I've done so far is:
GCD(987, 11)
987 = 89 * 11 + 8
GCD(11, 8)
11 = 1 * 8 + 3
GCD(8,3)
8 = 2 * 3 + 2
GCD(3,2)
3 = 1 * 2 + 1
...So basically, the GCD(987, 11) is 1.
So...
1 = 3 - 2
= 3 - (8 - 2 * 3)
= 3 - 8 + 2 * 3
= 3 * 3 - 8
= 3 * 3 - (987 - 89 * 11)
= 3 * 3 - 987 + 89 * 11
= 3 * (11 - 8) + 89 * 11 - 987
= 3 * 11 + 89 * 11 - 3 * 8 - 987
= 92 * 11 - 3 * 8 - 897
= 92 * 11 - 3 * (987 - 89 * 11) - 987
= 359 * 11 - 4 * 987
...But everywhere I've checked says that the answer to this is 7. How is 7 even possible??
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