The point of the form (a, a) always lies on:
(A) x-axis
(B) y-axis
(C) On the line y = x
(D) On the line x + y = 0
Answer:
(C) On the line y = x
Solution:
First of all we will discuss about x-axis
On x-axis, the value of y is always zero
Therefore point (a, a) cannot lie on x-axis as value of y-coordinate is given as ‘a’.
Now we will discuss about y-axis
On y-axis, the value of x is always zero.
Therefore point of the form (a, a) cannot lie on y-axis as value of x-coordinate is given as ‘a’.
On the line y = x, for each and every value of x there is an equal value of y
For example for x = 1, we get y = 1
Therefore point of the form (a, a) lies on the line y = x.
On the line x + y = 0
Let the value of x is 1
We get y = –1
Hence point of the form (a, a) does not lies on the line x + y = 0.
Therefore, the point of the form (a, a) always lies on the line y = x
Therefore option (C) is correct.