Original-----> Y=3X-7
First you want to isolate X on one side
So add 7 to both sides
Y+7=3X-7+7
Y+7=3X
Now divide by 3
(Y+7)/3=X
X=(Y+7)/3
Now rewrite X as Y and Y as X
Y=(X+7)/3
Now the Inverse is----> X=3Y-7
Have questions please let me know hope I helped