Question

calculate f(4) for each function below

Answer 1

Subtitute x = 4 to the equations:

$b)\ f(x)=\left(\dfrac{1}{5}\right)^x\to f(4)=\left(\dfrac{1}{5}\right)^4=\dfrac{1^4}{5^4}=\dfrac{1}{625}\\\\c)\ f(x)=3x-12\to f(4)=3\cdot4-12=12-12=0\\\\d)\ f(x)=(x-2)^3\to f(4)=(4-2)^3=2^3=8$