Statement 1: The line passes through point (-m, n).sud21 wrote:If line l passes through point (m,-n), is the slope of the line negative?
(1) The line passes through point (-m, n).
(2) mn is negative.
Slope = (n-(-n))/(-m-m) = 2n/(-2m) = -(n/m).
If m and n have the same sign, then the slope is negative.
If m and n have different signs, then the slope is positive.
INSUFFICIENT.
Statement 2: mn < 0.
Thus, m and n have different signs.
If m=1 and n=-1, we know that line L passes through (m,-n) = (1,1), but the slope could be positive or negative.
INSUFFICIENT.
Statements 1 and 2 combined:
Since the slope = -(n/m), and m and n have different signs, the slope is positive.
SUFFICIENT.
The correct answer is C.
