Respuesta :
Answer:
We obtained the two exponential functions:
- [tex]y\:=\:\frac{7}{27}\left(3\right)^x[/tex]
- [tex]y\:=-\:\frac{7}{27}\left(-3\right)^x[/tex]
Step-by-step explanation:
As we know that the exponential function is of the form
f(x) = abˣ
Given the points
- (3, 7)
- (5, 63)
We know these points belong to the exponential function.
so substituting the values (3, 7) and (5, 63) in the function
putting (3, 7)
y = abˣ
7 = ab³
also putting (5, 63)
y = abˣ
63 = ab⁵
Considering the 2nd equation
63 = ab⁵
as
[tex]a^b\times \:a^c=a^{b+c}[/tex]
so
63 = ab³×b²
substituting 7 = ab³ in 63 = ab³×b²
63 = 7 × b²
b² = 63/7
b² = 9
b = ± 3
If b = 3
plug in b = 3 in the equation 7 = ab³ to find the value 'a'
7 = ab³
7 = a(3)³
7 = a × 27
a = 7/27
so, a = 7/27 and b = 3 would give us the function
y = abˣ
[tex]y\:=\:\frac{7}{27}\left(3\right)^x[/tex]
if b = -3
plug in b = -3 in the equation 7 = ab³ to find the value 'a'
[tex]\:7\:=\:a\left(-3\right)^3[/tex]
[tex]a\left(-27\right)=7[/tex]
[tex]a=-\frac{7}{27}[/tex]
so, a = -7/27 and b = -3 would give us the function
y = abˣ
[tex]y\:=-\:\frac{7}{27}\left(-3\right)^x[/tex]
Thus, we obtained the two exponential functions:
- [tex]y\:=\:\frac{7}{27}\left(3\right)^x[/tex]
- [tex]y\:=-\:\frac{7}{27}\left(-3\right)^x[/tex]