Which statement about parallel lines is not true? a. they lie in the same plane. b. they never intersect. c. they share, at most, one point. d. they have slopes that are equal.

I would say C: They share, at most, one point because they don't share any points whatsoever. 

Where m is the slope of the line and b is the y-intercept of the line, or the y-coordinate of the point at which the line crosses the y-axis. to write an equation in slope-intercept form, given a graph of that equation, pick two points on the line and use them to find the slope. this is the value of m in the equation.