Question

The table of ordered pairs (x, y) gives an exponential function.

Write an equation for the function.
X
-1
0
1
2
y
1
3
2
12
72

Answer 1

y=2·6^2

Explanation:

Use formula y=a
`b^x`, plug in two different points.

72=ab^2

12=ab^1

isolate one so that a is on one side

a=
`(12)/(b)`

plug in a into the other equation

72=
`(12)/(b)`
`b^2`

72=
`(12b^2)/(b)`

72=12b

b=6

complete solving for a now

a=2

now put it back into
`y=ab^x`

y=2·6^2