I want to find d from 7*d mod 40=1 But error .help me please.

I tried the codes but thereis no error shown. Matlab instead asked for/tried to open some matlab files

syms d Eqn=='7*d==1'; Sold=solve(eqn,d,Domain=Dom::IntegerMod(40))

Answer 1

[Azzi Abdelmalek]

syms d
Eqn=7*mod(d,40)-1;
Sold=solve(Eqn,d)

[Sakunrat Jaejaima]

7*d mod 40==1 ans 23 Why you do = 1/7

[Sakunrat Jaejaima]

I want to solve the equation in mod.what to do