def calculate_x(y0, c, m):
	"""
	Calculate the expected value of x in the eqn. y = mx + c given the following paramters.

	Parameters
	----------
	> `y0`: the predicted value of y
	> `c`: y-intercept of the regression line
	> `m`: slope of the regression line

	Returns
	-------
	The expected value x0 for the above given parameters.
	"""

	return (y0 - c) / m