d)
To determine the type of function, we would compare the y values. If the ratio of consecutive y values is the same, then the function is exponential. We have
2/1 = 4/2 = 8/4 = 2
Thus, it is an exponential function. The general formula for an exponential function is
y = ab^x
We would find a and b
Substituting x = 0 and y = 1 into the formula, we have
1 = ab^0
1 = a
Substituting x = 1 and y = 2 into the formula, we have
2 = ab^1
2 = ab
Substituting a = 1 into 2 = ab, then
2 = 1 * b = b
By substituting a = 1 and b = 2 into the original formula, the equation would be
y = 2^x