Pls help me −12+16+(−18).

Ineed to know how to write question one in mathematical terms

Hurry can a triangle can be constructed with angles measuring 115°,55°, and 20°? yes or no

Martha is training for a duathlon, which includes biking and running. she knows that yesterday she covered a total distance of over 55.5 miles in more than than 4.5 hours of training. martha runs at a speed of 6 mph and bikes at a rate of 15.5 mph.