Can you please help with these six questions because i don't understand it..

If f(x)= 2x and g(x)=x-4, find f(g(3)).

A. -2

B. 6

C. 2

D. -6

An initial population of 78 rare animals is growing at an animal reservation at rate of 17% per year. Write an expression to model how many animals will be there in 3 years.

A. 17(1-0.78)^3

B. 17(1+0.78)^3

C. 78(1-0.17)^3

D. 78(1+0.17)^3

The temperature of a machine as it cools is modeled by equation

T=1890.73^t+45

Where T isdegrees in Celsius t is time in minutes. How does it take the machine to cool down 76 C?

A. 3.1 min

B 3.8 min

C. 5.7 min

D. 2.1 min

If f(x)=3x and g(x)=7x-1, find g(f(5)).

A. 104

B. 105

C. 102

D. 103

If f(x)=2x+1 and g(x)=x^2+2x+1, find f (g(x)).

A. 2x^2+4x+3

B. 4x^2+2x+2

C. x^2+2x+3

D. 4x^2+8x+4

You can buy a car for $8000 the depreciates at rate of 11% a year. How much is the car worth after 5 years?

A. $5689.12

B. $9000.52

C. $4467.25

D. $3532.75