We're trying to find out if a line cuts through the first quadrant (top right).

ALL lines with a positive slope will cross through the first quadrant

SOME lines with a negative slope will cross through the first quadrant

I. the line has x-intercept=-1 Tells us that the line crosses the x axis at (-1,0). Whether it passes through the first quadrant depends on it's slope, which we don't have, so this statement is insufficient.

INSUFFICIENT

II. the slope of the line is greater than 1Tells us that the line has a positive slope, so it WILL pass through the first quadrant.

SUFFICIENT

AnswerBA vertical line has an undefined slope because slope = rise/run and a vertical line has a run of 0 (and you can't divide by 0) so the slope is undefined. A horizontal line has a slope of 0. The fact that statement 2 says it has a slope greater than 1 tells us it's not a vertical or horizontal line, and that it does cross the first quadrant at some point.