Question:
The point of the form (a, −a), where a ≠ 0, lies on
(a) the x-axis
(b) the y-axis
(c) the line y = x
(d) the line x + y = 0
Solution:
(d) the line $x+y=0$
Given, a point of the form $(a,-a)$, where $a \neq 0$
When $a=1$, the point is $(1,-1)$.
When $a=2$, the point is $(2,-2)$.
When $a=3$, the point is $(3,-3) \ldots \ldots$ and so on.
Plot these points on a graph paper. Join these points and extend them in both the directions.
You will get the equation of the line $x+y=0$.