+ b. if an equation of a line is not in that form, it must be put into that form before the slope can be found. ex. what is the slope of the line 5x + y = 3? ex. 5x + y = 3 needs to change to y = -5x + 3 once the equation is in the correct form, the slope is found, -5. • a line with a negative slope is a line that is going downhill. a line with a positive slope is a line that is going uphill. a line with a zero slope is a horizontal line and a vertical line has an 