Yes, there are cases where the value of [tex]\( x \)[/tex] or [tex]\( a \)[/tex] would cause a problem. In the given equation:
[tex]\[
\frac{3}{a} x - 4 = 20
\][/tex]
we must consider the value of [tex]\( a \)[/tex]. If [tex]\( a \)[/tex] were to be zero, the term [tex]\( \frac{3}{a} \)[/tex] would involve division by zero, which is undefined in mathematics. Hence, [tex]\( a \)[/tex] must not be zero for the equation to be valid. Other than this case, there are no specific values of [tex]\( x \)[/tex] that would cause a problem, as [tex]\( x \)[/tex] can take any value provided [tex]\( a \)[/tex] is not zero. Therefore, the critical issue to avoid is setting [tex]\( a \)[/tex] equal to zero.