What is the sign of the slope of a line with positve x and y intercepts?
If the x-intercept and y-intercept have the same sign, the slope is always negative. If they have different signs, the slope is always positive. Think about it this way – slope of a line is a lot like the slope of a ramp. It tells you about rise over run, or how steeply the ramp (line or function) changes, and in what direction. Lines that go up as you move from left to right along the x-axis have a positive slope – they are ramping up. Lines that go down as you move from left to right have a negative slope – they are ramping down. Draw your x- and y- axes and play with a straight edge to see how this works. Pay attention to how the intercepts (the places where the line crosses each axis) change as you change the orientation of the straight edge.
