Hi Sak32,

This DS question asks if a line has a slope of 0. This essentially asks "Is the line horizontal?" This is a YES/NO question.

Fact 1: The X-intercept is 0

This means that the line intercepts the X-axis at the origin (0,0). Unfortunately, we don't know anything else about the line. The slope could be positive (answer is NO), negative (answer is NO) or 0 (answer is YES).
Fact 1 is INSUFFICIENT

Fact 2: The Y-intercept is 0

This also means that the line intercepts the origin (0,0). We still don't know if the slope is positive, negative or 0.
Fact 2 is INSUFFICIENT

Combined, we have 2 Facts that tell us the same thing: the line intercepts the origin (0,0), but we don't know about the slope. We could have a NO or a YES answer.
Combined, INSUFFICIENT

Final Answer: E

GMAT assassins aren't born, they're made,
Rich