Often times in programming it will make sense to generalize a problem. One such way to create

a function to calculate a solution. You have learned how to define functions that return a value,

but in Scheme you can also define functions that return new functions as their return value.

Take the quadratic functions f(x) = x^2 + 2x + 3 and f(x) = 3x^2 + x + 1 for example. We don't

want to define a new function by hand for every quadratic polynomial we write. We can

generalize quadratic functions to f(x) = ax^2 + bx + c.

Your job is to write a function that takes the coefficients a, b, and c as arguments and returns a

function (using lambda) that can be evaluated at any x.

(define (gen-poly a b c))

(define test-poly (gen-poly 1 1 1))

(test-poly 1) ; returns 3