Question

i got the answer to this question wrong
A scientist counts 35 bacteria present in a culture and finds that the number of bacteria triples each hour. The function y = 35 • 3x models the number of bacteria after x hours.

Graph the function. (You do not need to submit the graph).

Use the graph to estimate when there will be about 550 bacteria in the culture.

Answer 1

http://prntscr.com/1048q3
i tried drawing the graph

Answer 2

y=35*3^x?

Answer 3

yeah, almost correct, the point you need is the intersection point.

Answer 4

\[\huge y=35\times 3x\]
You have that equation. y represents the number of bacteria formed. You must find x.

Answer 5

intersection of the horizontal line and the curve.
and its 35* 3^x

Answer 6

if the number of bacteria triples every hour use the function y=3*(3^x)

Answer 7

can you find that intersection with your graph utility ?

Answer 8

if you can't, you can use the desmos online graphing calculator

Answer 9

http://prntscr.com/10494e

Answer 10

do you need me to explain why you use y=35*x^3 ?

Answer 11

sure

Answer 12

every hour the number of bacteria is multiplied by 3, right?

Answer 13

ok

Answer 14

so the first hour, there will be 35 bacteria
the second hour, there will be 35*3 bacteria
the third hour there will be 35*3*3 bacteria
the fourth hour there will be 35*3*3*3 bacteria

Answer 15

right?

Answer 16

these values are at the start of the hour, so the time values are 0,1,2 and 3
you can see that the number of bacteria each time is 35*3^0, 35*3^1, 35*3^2 and 35*3^3.

Answer 17

ok then

Answer 18

so using the equation y=35*3^x, what do you get as the time where y=550?