A. Some lines have no slope. TRUE. Vertical lines have no defined slope.
B. The slope of a line is always positive.
FALSE. Slopes can be negative, zero or positive.
C. The slope of a line that moves up from left to right is positive.
TRUE. Example: y = 2x + 5 has a graph that moves UP as x increases.
D. If two lines have the same slope, then they are the same line.
FALSE. While this is possible, it does not consider the important case where two lines have the same slope but different vertical intercepts.
E. A steep line has negative slope. FALSE. Negative slope has little or nothing to do with the "steepness" of the line.