I need to solve this with congruence. What I already done is :
$$1234x+567y=89$$
$$1234x\equiv 89\bmod 567$$
$$1234\cdot17x\equiv 89\cdot17\bmod 567$$
$$20978x\equiv 1513\bmod 567$$
$$x\equiv -1513\bmod 567$$
$x_0=-1513$, so $x=-1513+567t$
Now I'm stuck here. I don't know how to search for $y_0$
Edit :
I found out I can change the equation into $567y\equiv 89\bmod 1234$
$$567y\equiv 89\bmod 1234$$
$$567\cdot 37y\equiv 89\cdot 37\bmod 1234$$
$$20979y\equiv 3293\bmod 1234$$
$$y\equiv 3293\bmod 1234$$
So $y_0=3293$ and $y=3293+1234t$
Did I get something wrong? Do I need to do more than this?
It seems like you have already solved the equation. Simply plug in $y$ and $x$ into your original equation and then solve for $t$ in the equation below:
$$1234x+567y=1234(-1513+567t)+567(3293+1234t)=89$$
It seems that $t=0$ is a solution. Which means $x=-1513$ and $y=3293$ are solutions to this equation.