Question

The points (other than origin) for which abscissa is equal to the ordinate will lie in the quadrant
(a) I only
(b) I or II
(c) I or III
(d) II or IV

Answer 1

(c) I or III

​Explanation:
If abscissa = ordinate, there could be two possibilities.
Either both are positive or both are negative. So, a point could be either (+,+), which lie in quadrant I or it could be of the type (-,-), which lie in quadrant III.
Hence, the points (other then the origin) for which the abscissas are equal to the ordinates lie in quadrant I or III.