Explanation:
we see, for x=-1 we get 3³
x=0 we get 3²
x=1 we get 3¹
so the function is definitely a 3 to the power of x version.
but we need to adapt the exponent a bit and correct x, so that at least for these 3 values of x the result is "running backwards".
the easiest way : 2-x as exponent.
it fits.
for x=-1 we get 2 - -1 = 3 as exponent.
for x=0 we get 2-0 = 2 as exponent.
for x=1 we get 2-1 = 1 as exponent.
so, the exponential function passing through these 3 points is
