Answer:
The initial temperature of the coffee was 90°C.
Step-by-step explanation:
The function representing the temperature of the coffee after x minutes is:
[tex]T(x)=70\cdot(0.80)^{x}+20[/tex]
T is the temperature in degree Celsius.
The initial temperature of the coffee will be at x = 0.
Compute the value of T (x) at x = 0 as follows:
[tex]T(x)=70\cdot(0.80)^{x}+20[/tex]
[tex]T(0)=70\cdot (0.80)^{0}+20[/tex]
[tex]=70\times 1+20\\=70+20\\=90[/tex]
Thus, the initial temperature of the coffee was 90°C.