Question

Point (a,a) lies on the graph of the equation 3y = 2x -4 find the value of a

Answer 1

Substituting (x, y) with (a, a), since we have:

3a=2a-4, which means that 3a-2a=-4, that is a=-4.

So, the point is (-4, -4).


Remark: a point which lies in the graph of an equation is a solution of that equation. So x=a, y=a satisfies the equation  3y = 2x -4, which makes our substitution legitimate.


Answer: (-4, -4).