Let
x---------> represent the number of miles Troy's has driven
y--------> represent the amount of gas in Troy's truck
we know that
the equation that represents the amount of gas, y, in troy' s truck after driving a certain number of miles, x is
where
m is the slope---------> 
in this problem the slope is equal to 
it's negative because the tank is going to be consumed
assuming he starts with a full tank
substitute in the formula above
therefore
the answer is
the equation 
Answer:
(2.4, -1.2)
Step-by-step explanation:
Start by moving the x and the y to the same side and moving the number across the equal sign in both equations. We should now have y-0.45x=-2.3 and 2y+4.2x=7.8. We can use the elimination method by multiplying the first equation by -2 to get -2y+0.9x=4.6 and 2y+4.2x=7.8. From there, add the two equations together, eliminating y (-2+2=0). We now have 5.1x=12.4; divide both sides by 5.1 to get x=2.4. Then, in any of the two equations, let's use y-0.45x=-2.3, substitute x with 2.4. Now we have y-1.08=-2.3. Add 1.08 to both sides to get y=-1.22; round that to the nearest tenth to get -1.2.
For this case we have a function of the form:
Where,
A: initial amount
b: growth rate (if b> 1)
n: time in hours
Substituting values we have:
We have then that the initial amount is:
If b = 1.85 then the growth percentage is:
Answer:
here were initially 20 bacteria.
The hourly percent growth rate of the bacteria would be 85%
