Solve the equation

Ans : a = 1 or -6/5

Question : Do we need to include -6/5

Contributed by YC

It is important for you to check if your answers are valid i.e are there any answers you would need to reject?

This is what I called **checking for validity of answers**.

Humairah says

I guess, we do not include -6/5 as there is no such graph of log(-a).

alwaysLovely says

Good answer. Absolutely correct!

Continue to participate!

Algebra says

Clearly the domain (admissible values of x for the argument of the function f(x)=lg(x)) of f(x) is (0, \infty). If a=-6/5, then 3a+2 is negative; therefore x=-6/5 is not admissible into the domain of function f(x).