For slope to be equal to -1. Lines must be perpendicular.
1.Both x intercepts are on -ve x side. Product of slopes +ve
2.Both x intercepts are on +ve x side. Product of slopes can be +ve or -ve.
St2: Both intercepts are of different sign
1. When both intercepts are less than 3 with one on +ve y side and on eon -ve y side. Product of slopes +ve
2. When one intercept is above 3 and one less than 0. Product of slopes is -ve.
Both the x intercept are on +ve x side. Both of y intercept are on opposite side. So the slope will be -ve for sure but may or may not be equal to -1.
SAID BUSINESS SCHOOL, OXFORD - MBA CLASS OF 2008