Question

Help! I have looked at so many lessons on writing exponential functions from a graph and nothing has helped.

Answer 1

Answer:

y = $8(-\frac{1}{2})^x$

Step-by-step explanation:

Let the equation of the exponential function is,

y = a(b)ˣ

Since the graph of this function passes through two points $(4, \frac{1}{2})$ and (3, -1)

For the point $(4, \frac{1}{2})$,

$\frac{1}{2}=a(b)^4$ ---------(1)

For second point (3, -1),

-1 = a(b)³ ---------(2)

Divide equation (2) by equation (1),

$\frac{\frac{1}{2}}{-1}$ = $\frac{a(b)^4}{a(b)^3}$

$-\frac{1}{2}=b^{(4-3)}$

$-\frac{1}{2}=b$

From equation (2)

-1 = $a(-\frac{1}{2})^3$

-1 = $-\frac{1}{8}a$

a = 8

Therefore, equation of the exponential function will be,

y = $8(-\frac{1}{2})^x$