Question

Which one of the following equations could describe the attached graph?

A. y=2^(x+6)
B. y=1.5^(x+2) -3
C. y=1/2^x +6
D. y=3^(x-1)

Answer 1

These are the answer choices written in proper form!

Answer 2

the easiest way to know is just use x = 0 that would give you a point then check if that point is in the graph

Answer 3

@JAMG so even in A it would be y=2^(0+6) ?? I'm kind of confused :(

Answer 4

Simple way:
If you take a point on the graph, (1, 1) or (2, 3), notice that when x =1, y =1
Using that, plug this into each of the formulas, x=2, y=3 is another choice which gives the answer. (Pick easy points to read from the graph, if they exist)

Conceptually:
x-r is a transformation that shifts functions to the right by 'r'
For example,
3^(x-1) is the graph of 3^x, shifted one unit to the right.

Answer 5

when x = 0
A y = 2^6 which is clealry a big number
B y = 1.5^2 - 3 which is a negative number
C y = 1/2^2 + 6 which is 7
D y = 3^-1=1/3 => (0 , 1/3)

Answer 6

oh so it would be D since that point is right on the graph?! :o

Answer 7

yep :D

Answer 8

thank you SO much & for explaining why it wasn't the other answers!! :)

Answer 9

if all have that point use x = 1 which is another easy number to compute :D

Answer 10

thank you very much :)

Answer 11

np :D

Answer 12

Refer to the attachment from Mathematica 8 Home Edition.