How do you find "m" & "e" in the theory below?

y = m(x^e) + b

x1 = 1
y1 = 1

x2 = 2
y2 = 8

x3 = 3
x3 = 18

but what is the actual equation to find "m" and "e"?
eg.

mx^e = ?

how do you get "x" out of the first side?

m?^e = ?x?