If f (x) is an exponential function where f(3.5) = 21 and f(6.5) = 69, then find the value of f(9), to the nearest hundredth.

Find the number of liters in 12.8 gal of gasoline. round to the nearest hundredths

What is the effect on the graph of the function f(x)=x when f(x) is replaced with -f(x)+4

Find the magnitude, correct to two decimal places, made by each of the following with positive direction of the x axis a) y= x the answer is 45° but i don’t know how