I thought it'd take longer than it did, it didn't. I didn't use any formulas or anything, just logic'd out 180 degrees for each triangle. I imagine a trig teacher would thwack me in the back of the head for not showing my work though.
I don't think you can. You end up with two angles that are unconstrained without using side lengths. I'll look again to be sure.
One can solve the big triangle, no problem
One can solve the lower three triangles
One can solve for the angle at the bottom of the triangle containing angle x
One can constrain angle x + the angle above x to 150 degrees
One can constrain the angle across from x + the angle above it to 140 degrees
I think that's it for simple visual inspection.