The answer is 160 because as you stated in the question the number of bacteria doubles every five minutes, and after 10 minutes there are 40. Therefore, after 15 minutes there are 80 (40 doubled is 80), and after 20 (another 5 minutes), the number of bacteria is the double of 80, which is 160.
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- PeaceLoveHappiness
Answer:

Step-by-step explanation:

Hope this helps!
The answer is 15w^2 + 225w
Key:
^ - Means that it is an exponent, in case you didn't know :)
First you subtract the two equations
x^2-2x+3-6x
You simplify that and get
x^2+4x+3 = 0
Now we solve using the quadratic formula.
We get x = -1 and x = -3.
Now we find the y values by plugging the x values into the equation.
f(x) is the same as y.
y = (-1)^2 - 2(-1) + 3
y = 1+2+3
y = 6
Now for the other x value.
y = (-3)^2 - 2(-3) + 3
y = 9+9
y = 18
So the two ordered pairs are (-1,6) and (-3,18)
200/160=1.25
200+160=360/1.25/160=200.8
so your answer is 0.8