Hello - your roof parts are slightly skewed from one another if you look closely:
if that is intentional, then you’ll need to use Intersect to find a curve of intersection and trim the objects with that - it might be tricky to trim the right bits - but since you say that you want to trim off the parts that stick out, I’ll assume you really want this to be a clean intersection.
The really the best thing to do is to make a V-shaped closed polyline and ExtrudeCrv - done!
If you have two cleanly intersecting slabs, that you want to clean up then you can splt or trim with a bisecting plane -
CutPlane is a good way to make one of these or use the
Trim using a
CutPlane. This makes an actual plane in the file that you can select and use as a trimming object. You can then delete the plane:
Trim using a vertical ‘InfinitePlane’ Notice I type ‘ip’ when prompted by Trim for the cutting objects, then Vertical and then I set the plane using the ‘Int’ Osnap. Iinfinite Planes are temporary, only for the one command then they disappear.