def evaluate_line(a: float, b: float, x: float) -> float:
    """Evaluate the linear function y = a + bx for the given a, b.

    >>> result = evaluate_line(5.0, 1.0, 10.0)  # y = 5.0 + 1.0 * 10.0,
    >>> result == 15
    True
    """
    return a + b * x