We have been given that the take home pay is $1500 and 22% is withheld as taxes.
Let us assume that the gross pay is x dollars. Therefore, take home pay must be 78% of x because 22% of the pay is withheld as taxes, so you get to take home only 78% of the gross pay.
Since we have been given that take home pay is $1500 and it is 78% of the total gross pay. Therefore, we can set up an equation:

Therefore, gross pay is $1923.08
Because it has already been factored, we can solve it straight away. Now, since m is a variable, we yield the same result if m = 0 or m = 3 because we have two components to this equation.
We can either have m = 0 or m - 3 = 0
Hence, m is either 0 or 3