Help needed fast I am
Confused!!!

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.

y=2x−1 5x−4y=1 is (1,1)(1,1) a solution of the system?

Points j and k plotted on the coordinate grid are two vertices of rectangle jklm rectangle jklm has an area of 7 square units point j is located at 2,1 and point k is located at -5,1 each vertex of the rectangle is located at a point that has integer coordinates. what is the perimeter of rectangle jklm? (need answer asap)