Question

Which exponential function goes through the points (1, 16) and (4, 128)?

Answer 1

Answer:

Here is the complete question (attachment).

The function which represent the given points are $f(x)=8(2)^{x}$

Step-by-step explanation:

We know that a general exponential function is like,$y=a(b)^{x}$

We can find the answer by hit and trial method by plugging the values of $(x,y)$ coordinates.

Here we are going to solve this with the above general formula.

So as the points are $(1,16)$ then for $x=1,\ y=16$

Can be arranged in terms of the general equation.

$ab^1=16$...equation(1) and $ab^4=128$...equation(2)

$a\times b=16, then\ a=\frac{16}{a}$

Plugging the values in equation 2.

We have

$\frac{16}{b} b^4=128,16\times b^3=128,b=\sqrt[3]{\frac{128}{16}} =\sqrt[3]{8}=2$

Plugging $b=2$ in equation 1.

We have $a=\frac{16}{b} =\frac{16}{2} =8$

Comparing with the general equation of exponential $a=8$ and $b=2$

So the function which depicts the above points =$y=8(2)^x$

From theoption we have B as the correct answer.