You're going to need to be a bit more specific. What is it you're asking us?
<span>17<=3-2x<=21
subtract 3
14<=-2x<=18
divide by 2
7<=-x<=9
now mutiply whole inequality by -1, this will reveres the inequality
-7>=x>=-9
or -9<=x<=-7
so there are mistakes in the line
the corrected lines are
17 less than or equal to 3 - 2x and 3 - 2x less than or equal to 21 (line one)
14 less than or equal to -2x and -2x less than or equal to 18 (line two)
-7 greater than or equal to x and x greater than or equal to -9 (line three)</span>
This is a perfect example of exponential decay. In this case the growth factor should be represented by a fraction, and it is! This forest, starting out with apparently ( 800? ) pine trees, has a disease spreading, which kills 1 / 4th of each of the pine trees yearly. Therefore, the pine trees remaining should be 3 / 4.
Respectively 3 / 4 should be the growth factor, starting with 800 pine trees - the start value. This can be represented as such,
- where a = start value, b = growth factor, t = time ( <em>variable quantity</em> )
____
Thus, the function can model this problem. The forest after t years should have P( t ) number of pine trees remaining.
Answer:
The energy used in 3.5 hours = 5.25 kilowatts
Step-by-step explanation:
Energy used by electric kettle:
- kilowatts
Time taken by electric kettle:
Electric kettle's rate in kilowatts per hour can be calculated by dividing the spent energy i.e. 2.25 kilowatts by the time taken i.e. 1.5 hours.
Therefore,
Electric kettle's rate = 2.25 kilowatts / 1.5 hour
= 1.5 kilowatts per hour
Thus, the energy used in 3.5 hours = 1.5 × 3.5
= 5.25 kilowatts
Therefore, the energy used in 3.5 hours = 5.25 kilowatts