Answer:
y
=
4
(
1
2
)
x
Explanation:
An exponential function is in the general form
y
=
a
(
b
)
x
We know the points
(
−
1
,
8
)
and
(
1
,
2
)
, so the following are true:
8
=
a
(
b
−
1
)
=
a
b
2
=
a
(
b
1
)
=
a
b
Multiply both sides of the first equation by
b
to find that
8
b
=
a
Plug this into the second equation and solve for
b
:
2
=
(
8
b
)
b
2
=
8
b
2
b
2
=
1
4
b
=
±
1
2
Two equations seem to be possible here. Plug both values of
b
into the either equation to find
a
. I'll use the second equation for simpler algebra.
If
b
=
1
2
:
2
=
a
(
1
2
)
a
=
4
Giving us the equation:
y
=
4
(
1
2
)
x
If
b
=
−
1
2
:
2
=
a
(
−
1
2
)
a
=
−
4
Giving us the equation:
y
=
−
4
(
−
1
2
)
x
However! In an exponential function,
b
>
0
, otherwise many issues arise when trying to graph the function.
The only valid function is
y
=
4
(
1
2
)
x
5.07, the 4 is the thousands
Step-by-step explanation:
The Answer Is
-4d + 7 = 3d
So, 7 = 3d + 4d
Then, 7 = 7d
•d = 7/7
= 1
So D = 1.
Answer is C.
For every option, sub in the value and find the answer that matches the equation!
Example for option A, F(x) = x + 4 and G(x) = x²
G(F(x)) = G(x + 4) ーー> sub in the value of F(x)
Let's take the subbed in value, (x + 4) as x, and this x will be the x for G(x).
∴ Since G(x) is x²
G(x + 4) = (x + 4)² ーー> remember (x + 4) is represented as x.
= x² + 16
∴ You know that the answer is not A, do this for all options and you'll find the answer, C!
