functions

f(x) = 3*x + 4  // function definition

f(2)  // function call
f(3)  // function call

g(x, y) = 3*x + 2*y  // function definition

g(1, 2)  // function call (with two arguments)
g(3, 4)  // function call


h(z) = z + x  // function definition
h(3)          // what is x?

m = 3
b = 5
f(x) = m*x + b  // function definition
f(2)            // function call
f(10)           // function call
m = 14
f(-4)           // function call