To find the point of intersection we make a simultaneous equation:
To solve for x try and do the following
1. Rearrange equation so the x's are on one side and the other letters are on the other
2. Cancel out any common factors (ba seems to be a clear one)
3. Try and isolate x by possible factoring and dividing through.
(if you are still confused pop the equation into symbolab it follows similar steps, and if you are still confused don't hesitate to shoot a reply)
Now once you solve for x here, it gives you the x cordinate. We now need to find the y cordinate. We do this by subbing the x cordinate (in terms of a,b, c) into one of the lines (try subbing it into the perpendicular line since its less tedious)