What is the answer to this

When a formula is solved for a particular variable, several different equivalent forms may be possible. if we solved a=1/2bh for h, one possible correct answer is h=2a/b . which one of the following is not equivalent to this? a. h= 2(a/b) b. h= 2a(1/b) c. h= a/1/2b d. h= 1/2a/b

Which fraction is not equivalent to 8/12 a. 2/3 b. 24/36 c. 4/10 d. 6/10

Find the nonpermissible replacement for binthis expression. b2/5b +5