CPhill

22)....I'm not a Physics major (or even minor!! ) but this one is based on Newton's Law of Cooling.......I don't believe we can answer the question unless we know how long it took for the center to cool from 180F to some lesser temperature.....we have to know this in order to find the constant of proportionality.....(Alan can correct me, if I'm wrong!!) ..also...is 120F the desired temperature??

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28)   This is given by     A = Pe^(rt)   where A is the accumulated amount, P is the amount invested, r is the interest rate (as a decimal) and t is the time....so we have....

A = 2000e^(.051*3) = about $2330.65

Here's the graph of the parent function, y = 2^x  (the red graph) and the transform, y = 2^x + 5 (the blue graph)

a) is this

A = 2000(1.04)³  ≈ $2249.73   ......where A is the amount after 3 years

b)   is similar, Nataszaa....just substitute "18' for the exponent of "3"

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c) so we have

2500 = 2000(1.04)^t    .......we are trying to find "t"......

First, divide both sides by 2000

2500/2000 = (1.04)^t   .......simplify this on the left

5/4 = (1.04)^t              ........take the log of both sides

log(5/4) = log(1.04)^t    ........and by a property of logs, we can bring the "t" "out front"

log(5/4) = t log(1.04)   .........divide both sides by log(1.04)

log(5/4)/log(1.04)  = t = about 5.7 years

d) is similar.....just replace "2500" with "3000" and follow the same steps....

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28)    P = 1,860,000(.984)¹²    .....where P is the population after 12 years.....

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And there you go, Nataszaa.....

So I assume we have

(3y³)³ ......... ???...............

=   27y⁹

Use the MIN function in Excel......

This page should help......

Thanks, Melody......

I'm afraid I don't understand your question.......

Let x be the weight of the cherries

Then (6-x) must be the weight of the oranges...since, together, they weigh 6 lbs.

So we have.....

(The weight of the cherries times their cost per pound) + (the weight of the oranges times their cost per pound) = (the total cost)     ....or......mathematically.....

x(5) + (6-x)(2) = 18   ....simplifyting, we get

5x + 12 - 2x  = 18       ......simplify again

3x + 12 = 18                ....subtract 12 from both sides

3x = 6      

x = 2 lbs. of cherries

9(-3r-7n)-6 use r=-6 and n=5 

9(-3(-6)-7(5)) - 6 =

9(18-35) - 6  =

9(-17) - 6  =

-153 - 6 =

-159

And there you go......

5-8d-4r use d=5 and r= -5  

5-8(5)-4(-5) =

5-40+20  =

25-40  =

-15