PLEASE ANSWER this is related to derivatives!!

Which values for a and b will create infinitely many solutions for this system of equations? ax-y=8 2x+y=b

Christina can paint 420 square feet in 105 minutes. which unit rate describes the scenario?

When a 757 passenger jet begins its descent to the ronald reagan national airport in washington, d.c., it is 3900 feet from the ground. its angle of descent is 6 degrees. how far must the plane fly to reach the run way? a. 37,106 ft b. 37,310.4 ft c. 23,456.6 ft d 2,492.7 ft