Answer:
300 doors.
Step-by-step explanation:
1.5 minutes for 1 door.
7.5 hours for 300 doors.
7.5 hours = 450 minutes.

Answer:
f(x) means y. So basically what is x when y = -2
Step-by-step explanation:
28 + (3x -2) + 28 = 6x
28+ (3x -3x -2) + 28 = 6x - 3x
28+ (-2) + 28 = 3x
28 - 2 + 28 = 3x
26 + 28 = 3x
54 = 3x
18 = x