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subhasis8877
- Senior | Next Rank: 100 Posts
- Posts: 77
- Joined: Tue Mar 10, 2009 3:10 am
The two lines l and k are intersecting in the first quadrant. A line with +ve or -ve x or y-intercept can have its slope of either sign and two non parallel lines can intersect each other in any quadrant.
(1) The product of two x-intercepts is positive, that means both the x-intercepts are either +ve or -ve. But the slopes do not depend on x-intercepts only; as slope of a line = - (y-intercept)/(x-intercept). Insufficient
(2) The product of two y-intercepts is negative, that means both the y-intercepts are of opposite sign. But the slopes do not depend on y-intercepts only; as slope of a line = - (y-intercept)/(x-intercept). Insufficient
Amalgamating (1) & (2) gives that with same signs of x-intercepts, different signs of y-intercepts would definitely generate two slopes of different signs, and hence their product will definitely be negative. Sufficient
IMO C
