Question

A heated piece of metal cools according to the function c(x) = (.5)x − 9, where x is measured in hours. A device is added that aids in cooling according to the function h(x) = −x − 2. What will be the temperature of the metal after 5 hours?

−7° Celsius

6° Celsius

9° Celsius

16° Celsius

Answer 1

Function c(x) represents a line with positive slope of 0.5, y-intercept of -9° Celsius and x-intercept of 18 hours, while h(x) is a line of negative slope of -1, y-intercept of -2° Celsius and x-intercept of -2 hours (absurd value). The two functions meet at x = 4.7 hours, less than 5 hours... and at x=5 hours, function h(x) over rides the cool down process...

Answer 2

@kirbykirby help lol

Answer 3

he explained it in a way that made no sense to me

Answer 4

is \(c(x) = 0.5x -9 \) or \(0.5^x-9\)

Answer 5

2nd one

Answer 6

So if the metal cools according to \(c(x)\), and you add a device to cool it according to \(h(x)\), then the overall cooling effect should be the result of \(c(x)+h(x)\)

and if it's for 5 hours, then you should replace all the x's with 5's, i.e. \(c(5)+h(5)\)

Answer 7

replace thm with just 5? or .5?

Answer 8

oooh wait

Answer 9

5, because x represent the number of hours

Answer 10

\[(.5)^{x-9} \] is whatit is supposed to be

Answer 11

\[(.5)^{5-9}\]

Answer 12

oh , then yes that's what you should plug in

Answer 13

that equals 16 by the way

Answer 14

the next cooling addition would be -5-2

Answer 15

well h(x) = -5-2

Answer 16

yep

Answer 17

so "add" that to 16

Answer 18

9?

Answer 19

yeah

Answer 20

thanks @kirbykirby seen my error... sorry @Avenged7x