Still a bit lost not seeing answer for double checking

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

Tyler enjoys the fish so much that after his birthday his family decides to take him to a famous aquarium a tank at the aquarium is similar to his tank with the scale factor of 8 how many times greater is the volume of the tank at the aquarium than the volume of tyler tank

Which of the following quartic functions has x = –1 and x = –2 as its only two real zeroes?