Answer
True.
Work Step by Step
Consider any a point from first and third quadrant each and calculate slope:
1. (2,3) and (-1, -2)
(3+2)/(2+1) = 5/3
2. (5,6) and (-4,-3)
(6+3)/ (5+4) = 1
Coordinates in first quadrant are positive and coordinates in second quadrant are negative. So, the ratio of differences between these coordinates will be always positive and so is the slope.
