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For the exponential equation [tex]y = 3.4(0.66)^x[/tex] is it a growth or decay function and what is the y-intercept and the rate of growth or decay?

A) Growth, y- intercept = 1, rate is 66%

B) Decay, y- intercept = 3.4, rate is 34%

C) Decay, y- intercept = 3.4, rate is 66%

D) Growth, y- intercept = 3.4, rate is 34%

Respuesta :

Answer:

Option: B is the correct answer.      

B)     Decay, y- intercept = 3.4, rate is 34%

Step-by-step explanation:

We are given an exponential equation as follows:

                    [tex]y=3.4(0.66)^x[/tex]

We know that any exponential function of the type:

                                [tex]y=ab^x[/tex]

is growth function if: b>1

and is a decay function if 0< b< 1

Hence, here we have: b=0.66<1

Hence, the function is a decay function.

Also, we know that the y-intercept of a function is the point where x=0

Hence, we take x=0

we have:  [tex]y=3.4\times (0.66)^0\\\\\\y=3.4[/tex]

Hence, the y-intercept is:   3.4

Also, the rate of a function is denoted by 'r'

where b=1-r

    ⇒ 0.66=1-r

   ⇒   r=1-0.66

    ⇒ r=0.34

Hence, the rate is: 34%

          option: B is the correct answer.