In the equation ax+by+c=0, where c is a constant, if a=b=0 then
it is not a linear equation
Given equation: ax+by+c=0 where c is a constant
If a=b=0, then the equation reduces to c = 0 which is a constant. So, it will not be a linear equation.
Also, if either of a or b had been zero, it would have become a linear equation in one variable.
If a = 0, then equation will be by + c = 0.
Similarly, if b = 0, then equation will be ax + c = 0.
Now, by + c = 0 and ax + c = 0 are linear equations in one variable.
If both a ≠ 0 and b ≠ 0, then the given equation would have become a linear equation in two variables.