What are the multiple choices
Answer:
A Exactly one solution
Step-by-step explanation:

Putting y=0 at second equation, we have

The unique solution is 
Answer:
Step-by-step explanation:
Say that your equation is 2x+4=8, x=2
you would plug in the 2 where your x is so, 2(2) +4=8
then you'd solve regularly.
Hope my answer has helped you!
Answer:
r = 0.0424 cm (3sf)
Step-by-step explanation:
it makes 150 rev/sec
1 revolution = 1 circumference = 2pi*r
so every second the spool goes through 2*pi*r*150 of distance
we know that the rate of pulling is 40cm/sec
so 2pi*r*150 = 40
r = 40/(2pi*150), which is 0.04244131816 cm.
check: Circumference is 2pi*r = 0.2666
now multiply by 150rev/sec = 40 cm/sec
I think think that the answer is 4096, but I am not for sure.