Friday

September 4, 2015
Posted by **Tristan** on Tuesday, February 19, 2013 at 6:00pm.

- math quiz tomorrow -
**Reiny**, Tuesday, February 19, 2013 at 7:04pmwhy don't you just get yourself a few ordered pairs for each one ?

e.g. for

y = 2(3^x) - 3

(0, -1), (1, 3) , (2,15) , (3, 51) , don't graph the last one, rather just visualize where it is, and what happens if x gets larger

if x = -1,

y = 2(1/3) - 3 = -2.33 ---(-1, -2.3)

if x = -2

y = 2(1/9) - 3 = appr -2.78 ----> (-2, -2.8)

..

if x = -5

y = 2(1/243) - 3 = -2.991 ----> (-5, -2.99)

so clearly the graph approaches -3 as you go to the left, and it rises sharply as you go to the right

the y-intercept is 0,-1)

for the second one,

y = -3 ( 3^-x )

eg.

if x = 0 , y = -3(1) = -3

if x = 1 , y = -3(3^-1) = -3(1/3) = -1

if x = -1 , y = -3(3^1) = -9

if x = 2 , y = -3(3^-2) = -3/9 = -1/3

if x = -2 , y = -3(3^2) = -27

that should be enough to show what is happening.