Create a user-defined function that will solve for the largest real root of the equation

ax² + bx + c = 0

If no real roots (real roots exist only when b² - 4ac 0), then display an error message.

Your function should take three numbers as input (a, b, and c) and return the largest real solution. Test your function with these three cases:

a = 1, b = 3, and c = 2 (roots = 1 and 2)

a = 1, b = 1, and c = 1 (roots = (1 sqrt(3))/2 --> non-real)

a = 1, b = 1, and c = 1 (roots = (1 sqrt(5))/2 = -0.618 and 1.618)