Marie is logging the number of radioactive isotopes she observes every minute. She has determined her function to be f(x) = −4x + 120.

Based on the situation above, describe any necessary restrictions to the domain and range. Provide justification for the restrictions.

@jim_thompson5910 can u pleaaase help me out! last question and I cannot move ahead because I'm stuck on it :/

Question

Marie is logging the number of radioactive isotopes she observes every minute. She has determined her function to be f(x) = −4x + 120.

Based on the situation above, describe any necessary restrictions to the domain and range. Provide justification for the restrictions.

@jim_thompson5910 can u pleaaase help me out! last question and I cannot move ahead because I'm stuck on it :/

anonymous · Answer

@amistre64

anonymous · Answer

lol please help me! @jim_thompson5910

jim_thompson5910 · Answer

So the function is $$\large f(x) = -4x + 120$$ or is it supposed to be exponential?

anonymous · Answer

idk.. which makes everything much harder for me.. @jim_thompson5910

jim_thompson5910 · Answer

ok I'll assume it's linear

jim_thompson5910 · Answer

do you know how to graph this?

anonymous · Answer

yes

jim_thompson5910 · Answer

can you draw a rough sketch on here?

anonymous · Answer

i think.. i'm pretty sure i'm wrong

jim_thompson5910 · Answer

it doesn't have to be perfect

just the basic idea is fine

anonymous · Answer

okay :)

anonymous · Answer

|dw:1412902203511:dw|

jim_thompson5910 · Answer

ok add in the x and y axis as well

anonymous · Answer

ok

anonymous · Answer

idk how to do it. :/

anonymous · Answer

|dw:1412902421950:dw|

anonymous · Answer

is that any better? @jim_thompson5910

jim_thompson5910 · Answer

120 is the proper y intercept

but -4 is not the x-intercept

jim_thompson5910 · Answer

y = -4x + 120

0 = -4x + 120 ... plug in y = 0

solve for x to get the x-intercept

anonymous · Answer

|dw:1412902650415:dw|