Posted by Tristan on Tuesday, February 19, 2013 at 6:00pm.
why 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.