Question

Find the nonpermissible replacement for a in this expression 3/4a

Answer 1

they are correct the answer is 0

Answer 2

Under the assumption your expression is
`(3)/(4a)`, a cannot equal 0. If a=0, then 4a=0 and we have division by 0, which is undefined.
If your original expression was
`(3)/(4)a`, a could be any real number.