11-2m-(n+5+(-m)-3n+8)
11-2m-n-5-m+3n-8
Answer: -2-3m+2n
Hmmmm well I would first round the 1 and make it a 0 round the 9 and add to 6 and round 7 (was originally 6) to add 1 to 25 and then round 26 to 30
True: A face of a polyhedron is simply a flat boundary that helps forms the 3D solid.