Helllohello help please if you want -

Which equation results from adding the equations in this system? x+6y=9 and -x+2y=-15

Awater holding tank measures 105 m long, 50 m wide, and 8 m deep. traces of mercury have been found in the tank, with a concen- tration of 60 mg/l. what is the total mass of mercury in the tank? answer in units of kg.

Find the percent cost of the total spent on each equipment $36, fees $158, transportation $59 a. 14%, 62%, 23% b. 15%, 60%, 35% c. 10%, 70%, 20% d. 11%, 62%, 27%