Find all values of x where the tangent lines to y = x and y = x are parallel. X = If there are multiple values, simply separate them by commas. E.g. "5/7, 4/5" Problem 2. (1 point) Find an equation for the line tangent to the graph of f at (1, 6), where f is given by f(x) = 5x3 - 5x2 + 6. y =