Answer:
Domain: all real numbers. Range: (-∞, 2000]
Step-by-step explanation:
f(x)=2.5x is a simple "ramp" function, a linear function and a polynomial. As such, its domain contains "all real numbers." That value 800 defines the largest value that this f(x) can have: f(800) = 2.5(800) = 2000.
Thus, the range is "all real numbers from -∞ through and including 2000."
The sister catches up Jeff after 2 hours
Step-by-step explanation:
We can write Jeff's position and his sister position at time t using the following expressions:
- Jeff position:

where:
7 is the initial position of Jeff when his sister sarts chasing him
2.5 is Jeff's velocity (in miles/hour), so its position increases by 2.5 miles for each hour
t is the time measured in hours
- Sister position:

where
6 is the sister velocity (her position increases by 6 miles for every hour)
t is the time measured in hours
The sister catches up Jeff when the two positions are equal, so

And solving for t,

So, the sister catches Jeff after 2 hours.
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Answer:
$28.80
Step-by-step explanation:
4.80 x 6 = 28.8
Hope this helped!
Answer:
25. 
26. 
Step-by-step explanation:
For 25:
(area of a trapezoid)
(substitute terms)
(collect like terms)
(reduce the fraction by crossing out 2)
(calculate)
For 26:
(equation of area of a circle)
(enter the radius)
(communtative property to reorder the terms)