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]